from what position did he raise? from the description it sounds like the button.

he sounds like the kind of player that would open-raise on the button w/ a huge range. if so, i would 3-bet pf for value, though just calling is not horrendous.

i think just check-folding this flop is giving up too much, somewhat depending on what the "xx" cards are. you are ahead of him a whole lot here and, even if not, will often have at least 6 outs.

i would at least call the flop, and definitely showdown if you improve your hand. i would also be calling down unimproved quite a bit based on the final board texture. (for example, if the board comes A2327, or AJ442, you will be good often enough to warrant calling all the way.)

one key against maniacs is certainly to punish them mightily when you have the goods, but you should also be looking to almost always showdown against them when you have a showdown-worthy hand. and in this situation, KTo is showdown-worthy.