Check preflop, bet flop. If you miss turn, just don't do anything stupid. I'd probably c/c with odds.

If you hit turn, keep betting.

Raising his limp preflop is pretty bad. You have a hand that plays like shit oop against a guy who loves to bluff. If he were straightforward/weak and passive, then raising A2 still isn't that great because you could still exploit the fact that he's weak and passive with any two other cards.

"Zomg A-high" is not a reason to get into shit spots oop.