So....
I've been sticking to basically a single party, until I went to the mage tower and it was switched up a bit.
Anyhow, I went back to camp and thought... what the heck, im going to use those other party members. WOW... random world map encounter! party whiped out!
But, the point is that I realized that even the party members you're not currently using accumulate experience points. So, that is pretty good since there is no grinding. I'm going to Fully upgrade Liliana's lock picking and go back through the mage tower to see if there's any epic loot in the chests I couldn't get.
Such a good game... 30-35 hours in and no near in sight!