I think my turn bet here is a mistake, since I'm not getting called by many worse hands. Was the fold on the river good though?

PokerStars - $0.10 NL FAST - Holdem - 9 players
Hand converted by PokerTracker 4

BTN: 134.1 BB (VPIP: 11.34, PFR: 6.19, 3Bet Preflop: 7.50, Hands: 97)
SB: 54.1 BB (VPIP: 19.44, PFR: 0.00, 3Bet Preflop: 0.00, Hands: 36)
BB: 47.8 BB (VPIP: 17.39, PFR: 17.39, 3Bet Preflop: 18.18, Hands: 24)
UTG: 60.3 BB (VPIP: 0.00, PFR: 0.00, 3Bet Preflop: 0.00, Hands: 11)
Hero (UTG+1): 107.5 BB
UTG+2: 177.9 BB (VPIP: 10.00, PFR: 10.00, 3Bet Preflop: 0.00, Hands: 10)
MP: 118.7 BB (VPIP: 0.00, PFR: 0.00, 3Bet Preflop: 0.00, Hands: 9)
MP+1: 97 BB (VPIP: 10.00, PFR: 0.00, 3Bet Preflop: 0.00, Hands: 10)
CO: 100 BB (VPIP: 0.00, PFR: 0.00, 3Bet Preflop: 0.00, Hands: 9)

SB posts SB 0.5 BB, BB posts BB 1 BB

Pre Flop: (pot: 1.5 BB) Hero has K K

fold, Hero raises to 3 BB, fold, fold, fold, fold, BTN raises to 6 BB, SB calls 5.5 BB, fold, Hero raises to 20 BB, BTN calls 14 BB, fold

Flop: (47 BB, 2 players) A 5 2
Hero checks, BTN checks

Turn: (47 BB, 2 players) J
Hero bets 30 BB, BTN calls 30 BB

River: (107 BB, 2 players) 8
Hero checks, BTN bets 51 BB, fold

BTN wins 102.2 BB

Yep, always a nasty spot.

I'd be looking to check/evaluate every street, don't like the turn bet. At least make it smaller as all we're really doing is betting to prevent him from bluffing us off KK with QQ! I'd probably call one moderate sized bet and be done if he wants to put stacks in.

EP vs BTN 4bet pot versus fairly random tight player, expect ranges to be super strong. He likely has AA based on his line. BvB versus a more active reg and we might be less keen to fold.

sometimes I like to check the turn also and call the river

As played,it was a good river fold