I think the line is fine. OTR, you don't beat (m)any calls, right? And getting better PPs to fold is too ambitious vs an unknown, I think.

Valuebetting up to halfpot seems better than checking back,
since it is micro stakes and he is an unknown.
You have to be aware of the smaller half pot sizings OTF and OTT, which keep villain his range wider and weaker. As played by villain I don’t expect too many Kx or better OTR after he checks.
The bulk of his range is Ahigh/22-44/77-88 and a few 9x (a9/k9), slowplayed 6x and Kx (discounted heavily).
You need ( some) A-highs to call OTR to have >50% vs calling range OTR. Therefore, I prefer 33% sizing OTR. The king is a scarecard and betting bigger will likely tilt him to call narrower, thereby plunging the EV of your riverbet.

Turnbet is really good and important with 66 here. ��
It would be a big EVloss if you would forego that play.

I like checking back river, K is decent card for our range so don't think villain have a ton reasons to be herocalling wide (Ace highs).
Don't think betting is a mistake tho

Turn you must bet bigger, you have more than 30 combos nutequity advantage, every Turn card that is lower than a Q is very good for you and is increasing your range/nut equity advantage, since you can basically Cbet the Flop merged (full range) for a half pot sizing.

def check back river 101% (what hands do you want to call you?)