Table is 1-2 8 handed. Stack sizes vary between about 120 and 800. Hero has about 300.
In hero's view stack sizes are largely irrelevant to this hand....
The table is pretty nitty at the moment, with one mawg slag who is raising 90% of hands and barrelling most flops and turns, he is to hero's 2nd left.
Hero looks like an absolute rock as he has been card dead for at least two hours, and with all the table aggression to his left has stayed quiet.
4 limpers, hero is on the button with k4ss and decides to raise to 12 (mind fart here with almost guaranteed aggression from bb?)
BB raises to 28, 2 callers, hero calls from button. (should we fold here, Im getting great odds but is rio to high to call?)
Flop come kh, js, 6d pot ~115)
Mawg slag checks
Old guy from utg+1 bets out 40. (not your typical old guy nit, can easily be betting a j here)
Fold, hero calls, (king can be good here, and I have backdoor hearts.... Should I just fold)
Mawg slag calls
Turn is 7s pot ~230
Mawg slag checks
Old guy bets 10? Hero calls, mawg calls.
River is As pot ~260
Hero has 220 ish behind. Mawg covers easily, old guy has similar to hero.
Old guy checks, how much should hero bet here?

When a SLAG checks as aggressor pre, that should sound alarm bells.
That said, fold pre. You know BB is going to raise, you assume he'll get callers, you have position but a **** hand.
OTF you barely hit and are facing aggression from someone other than the pf raiser...it's a goddamn mess and you've got just enough of a piece to convince yourself to hold on. Don't.

^this wasn't untypical from the mawg oop,
I was expecting him to fold flop tbh, and as I stated the old guy is a pretty poor player, could easily be betting a j or even a 6 here....
I thought pretty hard about the flop call,

Your right to suggest this hand was a mess, I was frustrated I think with being so card dead for so long with a slag to my left,
I was seduced by the maths of a small raise pre with callers, and then the flop I just felt like I had called pre, what was the point if I was just going to fold to one bet when I have top pair.... ( I know the precise reason I should fold pre right?)

I actually think flop is ok to peel one. Hand is fairly standard outside of preflop. If you are going to raise K4s on the button pre, it needs to be much larger than $12 after 4 limpers.

In this case, with the aggro in the BB, it's probably a bad spot to be raising a hand like this pre. If you are going to raise, $20 minimum after 4 limps.

Once you've raised and it gets repopped to $28, I'm ok with calling $16 more closing he action when it gets back to us.

On the flop, I'm definitely peeling 1 for a 1/3 PSB but I am planning to fold to most turn bets unimproved.

On the turn, calling is fine, but I would consider a raise against this weird line as well. Calling is fine though.

On the river, just shove. We have less than a psb remaining.

^^^
I think this is the trouble with this hand. Hero gets uppity trying to play position (that comes off like I'm being negative, but I don't mean it quite like that) but isn't quite getting it right, which leads to problems all the way down the line with really uncertain holdings. I'm not against the raise pre per se, but sizing is the issue. And with the donking and check/calling, I really get mubsy here with TPNK. That's why I think a plan is important and following it, even when the BDFD hits the turn, is imperative.

Obviously fold preflop. If I was going to call the 3bet, I would not continue the hand unless I hit the flop hard, ie two pair, three Ks or three fours.

Fold pre.
Fold the second time around.
Flop peel might be alright given the price, but it's pretty meh.
Turn is a pretty easy call given the lol sizing.
We can basically call looking for a 1 outer profitably.
River seems like a cram it in.

On the river hero bet 70 in a hope of mawg slag looking at it as a weak bluff and would jam on me, both the mawg and old man turbo folded....
Would a jam have looked weaker here?
What about raising turn here, or is that just turning a hand with decent sdv into a bluff?
It was a weird hand, I was frustrated and tried to get creative, I really didn't know what to do facing the three bet pre, even though I stupidly new it was coming, and the flop I had no clue what was best, or where I was.... Is this what being a fish is like? it was nice binking the nuts on the river tbf.

This is why we don't play K4.

As played I'd bet the river tiny like $40