Segment 1: Beginning to Drake Castle Rest Area (I guess that's what it is?)
I've learned that despite the fact that this game has a reputation for being a grind fest, you actually level quite fast early on when you head straight through the game instead of sticking around to continually gain levels. When you actually take the time to fight the random battles, you gain levels faster than I would imagine. I guess there's a bit difference between leveling to 4 at Rim Elm when you get ~ 40 EXP per battle and leveling to 4 by rushing to the end of Drake Castle. The fights with 2x Skeleton yield 117 EXP and Gimard + Skeleton is 100 EXP per fight. As such, I'll get to the end of Drake Castle at level 4 (I didn't think I'd get that high without stopping, but then I realize that that's not so high after all.) Given that there's 500 more EXP to L5 and the battles on Rikuroa give an absurd amount of EXP (I think it's upwards of 250), I'll probably be L5 or maybe L6 just from random battles. I'm quite honestly surprised at this turn of events.
I think that Ram may be correct - without deliberately running from fights, it may not be possible to get to Juggercort before 39. I'm not so sure it's quite that high, but I could easily see it being 37.
Next update will be up in an hour or so - hoping to get to Caruban tonight.
Update: Segment 2: Noa to Caruban
The enemies on Rikuroa give a ton of EXP. Something like 80 per enemy. And while that's not all that much when divided among three characters, 250 per battle is quite a bit, and even ~170 isn't too shabby either. Except, when you're trying to keep your levels down and you can't run either. Then it is kind of a pain.
And to top it all off, I think I had the worst possible luck in the Caruban fight. He used Fire Breath. Every. Single. Turn. 4 times in a row!!! I had to burn the Healing Bloom, which I would have much rather saved for the Viguro, or even for Zeto if I could have done so.

Ah well, **** happens, so you might as well deal. I made a conscious effort not to use Vera while trekking the mountain. That way, Vahn's 42 MP at L4 (he leveled to 5 on the way, but he doesn't get that MP) allows him to cast 4 shots of Gimard before expiring. Noa got in one Tempest Break, then used the Healing Bloom, while Vahn summoned every turn. This turned out to be just enough to deplete Caruban, which is good - I don't think I would have survived another turn - certainly not if there was going to be another bout of Fire Breath coming my way.
Anyway, the 750 EXP is good for level 6 for both characters.
And I thought I was going to be fighting the Viguro at level 7.
Edit 2: Segment 3: The Voz Forest Sequence
Voz Forests went pretty uneventfully overall - the only thing of note was that I used a Door of Light to escape West Voz instead of running back to save time and a few battles. I should also note for the record that once you get up past about level 5, 250 EXP per fight doesn't level you up nearly as fast as it does in the early game, so gaining a level every other fight is a bit unrealistic, and that's a bit of an understatement.
This game is still a grindfest, but perhaps less so than one might give it credit. However, it's not a game where you can escape from battles haphazardly - the game can and will punish you for that severely. I find that rushing to get the treasures, but with no stopping to grind for G or EXP, the game isn't nearly as difficult as I would think, even if my levels are some 20% less than what they are during a "normal" run of the game, for whatever that means.
Viguro fight went decently - I made sure to concentrate all my firepower on one of the two first - while I fell under 50 HP a few times, I made sure to heal frequently with Healing Shrooms / Blooms (Leaves sell for more G, so I want to use the Shrooms so I can sell the Leaves for armor.) Also, I had a total of 6 Healing Blooms just from treasures (including the hidden treasures) up to the fight, so it's not like I had to conserve the one I used in the Caruban fight. By the way, my levels were 8/8/6 when I fought the miniboss, and they did not increase in the battle. With that said, however, I will almost certainly gain a level before I head off to Zeto's Dungeon, as I am no more than a couple hundred EXP away from advancement at this point. Oh, and no deaths up to this point either, which is really nice as well.

I will have to use a lot of healing leaves / shrooms throughout Zeto's dungeon, since my max MP is somewhat less than what I'm used to. Oh, and I definitely picked up the Deep Sea Jewel in West Voz - I can't afford a second one, but this should help greatly against the final boss of
this game Drake Kingdom.
Levels: 9/9/7 (assumed)
Deaths: 0.
Resets: 0.
Segment 4: Berserker-Ser(u)ker. Oh, and Zeto too.
Strangely enough, no battles on the way to Zeto's dungeon, but I did gain a level soon upon entering the labyrinth. Receive Thunder Book I. Use Thunder Book I. Don't use it against Songi though. Whereas I normally would use 5-block Arts against the red-haired menace, that isn't an option at level 8, so I instead fired two rounds of Theeder to weaken him, then ended his last hundred HP with Gimard to save MP for Zeto. Received the Mettle Ring and gave it to Noa, received 1500 EXP, and received precisely zero levels for our spiky-haired friend.
Zeto battle went pretty smoothly - the Deep Sea Jewel and Cure Amulets I've found by this point really help to stave off the worst of his attacks, if only for one character. Still, at level 9/9/8, every advantage is one I will gladly take.

To be frank though, apart from using more Healing Blooms, the battle really wasn't all that different from doing it at level 12 or so. Just had to play the fight a bit more defensively and keep a stricter eye on my HP and MP levels. However, the same basic tactics proved effective. Vahn uses Double Tornado Flames, Noa uses Tempest Break (which is easily her most used technique, mind you), and Gala performs support. Everyone gains a level from this fight, bringing the teams levels to 10/10/9
At this point, I decided that a bit of Out-of-Order-Sequencing is wise. Went to Jeremi and immediately left. Headed over to Vidna, got the Fishing Equipment, got a bonus game on the first try, got ~ 2000 coins, and picked up about 200 light lures (in groups of 99) to sell for cash, ending my G-related issues for the time being. Also got the War Soul and the Guardian Ring, as decent accessories come at a premium in this part of the game. I went ahead and got everyone some armor and better weapons while I was at it, since the nature of this sort of run is one where one's wallet ends up a bit lighter than one would like. Then, it was off to Octam to pick up the Orb spell, I mean, go take care of story-related matters. Saw Cara, found out about the Star Pearl in Jeremi. Noa exclaims how Zalan must be the one who has the Star Pearl, despite his name never being mentioned at any point. On the flipside, when you don't visit Sashia in Vidna, Gala's dialogue about the mechanism with the Books of Prophecy changes.
So, it's on to Jeremi now - run up to the Sky Gardens, pick up a treasure or two on the way, then time for the difficult, painstaking, and agonizing fight with the Berserker. Oh, who am I kidding?! Cheap shotted him by spamming Nighto until he was annihilated. He never even got an attack in, since he spent the whole fight confused. Vahn's Nighto spell leveled up too, which is basically meaningless since I'm never going to use that spell the rest of the game.

Sadly, I did have to use both Magic Leaves.

Oh well.
Get the treasures in town, go do the Zalan-Pepe sequence to advance that little subplot, and then it's off to the Shadow Gate (or is it the Gate of Shadows?)
I should point out that after the Berserker fight, my levels are 12/12/11, which is a little low, but not unbearably so. I guess fighting the random battles has a way of making sure that you stay at some sort of minimal level sufficient to beat the bosses of this game, albeit with great difficulty (though granted, the Zeto and Berserker fights are kind of a pain. Still, it's better than the Xain fight is going to be. Dreading that already.
Amusing note: Gala still has no head armor at this point in the game.