bet / fold .. bet/call.. check call .. check fold.. check raise ?

Well, bet/call would be optimistic even against a maniac, and check/raise is kind of an adventurous bluff. Might work against this sizing...
x/c and x/f are close IMO. You're getting a good price, but it looks like he's inviting you to call with a thin valuebet. There are no worse hands that would valuebet here, so I'm guessing he has some better 2p hand.

Edit: There are also almost 0 unpaired hands in his range and most people don't turn pairs into bluffs, which makes me lean toward folding.

I would fold, villain can slowplay some straights OTT, or has just rivered a flush or better 2 pair and he doesnt have enough random double floats.

Fold is fine