Yeah, Menobe is another terribly confusing dungeon. Lots of steps that go in circles or nowhere. Plus, you should probably stay off the 4th floor (the first time in there) except when absolutely necessary (which it is ... twice). If you get jumped by 3 Shadows, it's most likely the end for your party. (Unless you have grinded excessively before you went dungeon spelunking on Dezo.) Using the snow crown helps, but if they get the first round free, even the healing items (Truth Slvs, Amber Robe, etc) won't save you in time
Among the first couple times I played PSII, I went to Guaron first. Only a couple bad levels in there. But the Vorcanos and Firdragons present a similar problem.
The "ghost type" monsters which infest the dungeons of Dezo are vulnerable to Kain's Brose as well as Hugh's Vol and Savol magic. But they all miss like 50/50. I think the dragons are too. Not sure if Sega meant that to be or not but you can take advantage of it.
The bottom of Ikuto and the 4th floor of Menobe are good places to level up if your party is around level 25+.