I'm just wondering if it's possible to solo this game. If so, what works?

I ask only because of the way XP is calculated. I'd guess that before the first chapter is over you'd be earning very little XP.

Possible? Yes.

Easy? No.

Fun? Hell yeah!

I've soloed the game before using a bizarre multiclassed Drow. If memory serves, it was along the lines of a rogue2/paladin2/ranger1/mageX, though I unfortunately can no longer access the game to find out.

As a Drow, I was behind enough in XP anyway to not really feel the lack of XP until much later, and with powergamed stats and an overpowered class combination, my mage was pretty much unstoppable.

If I were to solo a non-mage/sorcerer, I'd probably try a cleric of a god with offensive power, like Lathander. A Monk may also work, though I dislike soloing non-caster classes.