Had some fun this afternoon. I got all the way to Melenam using Lux and Esuna, playing at 85% most of the time.
It turned out quite a bit better than I had expected. Lux doesn't need equipment, and he hits harder than the alien, so I managed to kill Romus at level 3.
In retrospect, I should have bought two b power at the start, manipulated a bunch of potions (as I did after killing Romus, just to see if I could) and then bought one or two b prtct before taking on Romus.
None of the apprenti wanted to fight me, not that I think fighting an apprentice would be a good use of time, so I ended up using my last b power on a Trick to get a sapphire.
...I probably should have joined with the Demon. He learns vacuum earlier than Esuna, IIRC, and I can use that to kill brains/everything. Then again, vacuum is expensive; Valsu's buffing spells are cheap, and can be used against bosses.
Anyway, it's probably possible to get to Melenam in 20 minutes using a more efficient strategy, (sans backtracking) and with better fight evasion and manipulation, especially on the overworld... If I learned anything from doing this, it's that regular battles aren't worth diddly-squat compared to bosses.
Movie.