$1/3 game in Houston

I haven't played with Villain before but he was at the table when I sat down and seems friendly with the folks who I identify as regs. I don't usually play at this time of day so lots of the folks at the tables are unknown to me.

Anyway, villain is having a rough session but I'm not sure how much of it to attribute to his play vs the cards. I haven't seen him do anything I consider out of line but he's lost a lot of medium sized pots to top pair, so-so kicker type hands so maybe he's just too sticky postflop. I don't feel like he's calling my pre-flop raises at an unusually high frequency, but I don't know that he's folded any of his button straddles to me. He's definitely betting in position a lot on multi-way flops when it checks to him in late position, and I think he's betting a bit too much in those spots (e.g., 2/3+ pot). They're spots where it doesn't make sense for him to being betting air, but the frequencies seem too high to me.

Villain has ~$1200 and I cover

Button (Villain) straddles to $6
SB calls $6
BB calls $6
UTG is the softest spot at the table and calls $6 as well
UTG+1 folds
LJ calls
HJ (Hero) has A A and raises to $45
CO folds
Button calls $45
SB calls $45
BB calls $45
UTG calls $45
UTG+1 folds

Flop ($231) K 7 5 (2 diamonds, can't swear the K wasn't one of them)

Checks to Hero, I check as well. I'm expecting Villain to bet in position with a wide range and I'm expecting him to make it a good sized bet based on observed tendencies from this session.
Villain bets $110
Folds to Hero
Hero calls $110

Turn ($451) J

Hero checks
Villain bets $250
Hero calls $250, his hands were obstructing my view of his stack so I did ask to see what he had left before calling

River ($951)

Hero ??? This is where I was least certain. Not expecting many (any?) worse hands to bets the river for value, wondering if a $350 block bet is better than a check here? I wound up checking.
Villain bets $600
Hero ???

What is the River card?

My bad, certainly didn't mean to omit it, thanks for the heads up.

River was J

Based on villain's description, I don't know that I would rule out him just having like KQ here and I think I find a call. He is over defending straddle and losing a lot to top pair weak kicker. A K here is probably the nuts to him. He seems to bet too often and for too much. So I think I might just make a call based off of that.

I like CRing the flop to 380. You set up villain and he committed the error that you expected him to make, the problem is you didn't punish him for it and just give him a free card and option to take another free one because you know you are checking the turn.

Just letting him bluff $110 while letting him realize all of his equity seems bad.

As played this seems like a pretty standard call.

i like how you played it, now call

Preflop vs 4 limps you can go a touch larger, 50-60.

On the flop, checking is fine, however when you block draws and when there should be very few 2 pair hands out there, there is a very good chance that someone out there (maybe more than one) has a King so betti g small is also OK.

On the river I like a call. The only hands you should really be worried about are KJ, 77 and 55. You might see the occasional JXdd or something but rarely. He can bluff diamonds, 86s, 75s and as Mlark says you might see KQ value betting from time to time. You only need to beat maybe 4-5 combinations to be good and we can definitely find those.

JxXd too. But realistically that's like QJ, JT, maybe a few others if he really likes defending his straddle.

At the end of the day, so many low stakes players assume we never check AK or better on the flop, and so I am not surprised if he went three streets with a K.