chameleon. not sure what would be the best entry for you since you don't have access to tier 1 classes.
factotum is good usually. Might be able to factotum3/swashbuckler3 then enter.
Maybe human factotum (able learner feat), paladin4(getting turning and charisma to saves)/chameleonx.
Playing around with entry into chameleon can get you a lot of awesome front loaded abilities before you enter and then you get to use all those abilities along with the super adaptability of chameleon.