I think the checkraise on the turn is a spew. Whenever a calling station raises me on a flop like that, my first instinct is that he hit two pair, Ace-Small. I think a call-down is ok, but the one thing you need to keep in mind when you make a play like a check-raise is what do you intend to accomplish by making that play?

Normally, in a heads-up situation, you are using the check/raise to suck an extra bet out of a beaten player when you have a very strong hand. But since a passive player is raising you on the flop and all you have is top pair, there's really no need to suck an extra bet out of him even if you are ahead. I doubt he's savvy enough for a free card play on the off chance he's on a straight draw, so I think the raise indicates a made hand. I check and call down or possibly check/fold.