2/4 Absolute, couple hands against a LAG

[Somekid]

Villain is 78/28/1.7 through 61 hands, he sees a lot of showdowns. My main read was that if he's checked to, he almost always bets. I've seen him raise with draws, and once, absolutely nothing.

I felt completely lost playing against this guy. Should I be seeing showdowns in these hands?

Poster (CO) checks, and I raise on the Button with AJo.
Villain (SB) calls, BB calls, poster folds.

Flop comes: 8c 4c Kd
Villain bets, BB folds, I call

I think this flop call was okay. I'm getting 8-1 and I estimate myself to have 5 outs (3 pair outs--I'm not so sure he has a king, 1.5 backdoor flush outs, and maybe .5 a backdoor straight out). Also I guess I could be ahead here some small percentage of the time.

Turn: Jd
Villain bets, Hero calls

Should I just fold here? I decided to see a showdown since the villain was pretty laggy and didn't necessarily have a King.

River: 9s
Villain bets, Hero calls.

should I fold?

The next hand is even uglier, I have J5o in the BB. The game is now 3-handed.

Villain on the button calls, SB completes, I check in the BB with J5o.

Flop: Ks 8s 3h
checked around

Turn:5c
SB checks, I bet, Villain calls, SB folds

Is this even worth betting? I didn't think the Villain had anything that beat me, or he would have bet before.

River: 6d

I bet, Villain raises, I call (???).

A 6 is about the best card I could ask for on the river. I decided to bet again. I think I should have bet/folded? I didn't want to check since the villain would bet there 100%. Once he raises I make a horrible call. Although is it really that bad if I've seen the villain make bluff raises HU with absolutely nothing?

Also when I bet the turn, what do I do if a high overcard hits on the river?