1-2 NL at a local casino.
$200 effective stacks.
Villain is solid TAG player.

Hero limps UTG with KQ (bad play?)
Villain UTG+1 raises to $10
Folds to BB who calls as does hero.
Pot is ~$30
Flop is QT4
BB and hero check.
Villain bets $20.
BB folds.
Hero calls
Pot is ~$70
Turn is 4
Hero checks
Villain bets $50
Hero calls
Pot is ~$170 to the river
River is 7
Hero checks
Villain goes all in for $120
Hero calls.

I feel like check calling all the way was not optimal, but I'm not sure what would be better.

Depends on the table, but yes, generally bad. It requires a really passive table where it is likely to go multi-way unraised. KQ plays well multi-way, but HORRIBLY HU OOP.

Now this is bad play. V is a decent TAG and is raising in EP. You have a trouble hand OOP and really three-way is not enough here. You can't like TPGK in this circumstance, so you're really only playing for 2-pair plus.

AP: OTF, c/c is OK with TPMK, but this is exactly the situation you wanted to avoid by folding pre. Board is pretty dry, so you know he'd going to c-bet, and it means little, so calling once is OK, but you have to make sure you don't get committed with TPGK.

Fold turn. Sure, he has some double-barrel with air in his range, but not a whole lot, and if you call turn you are committed to calling river with a weak hand.

AP: You're kind of forced to call river, but you're going to lose often. Biggest mistakes were PF and turn, imo.

Don't post results. I didn't read them before posting, but many others will and it will skew their analysis.

I usually fold this hand in EP and if I do choose to play it I would come in for a raise. On this board I think check calling is best, but I would fold on the turn if you say villain is a solid TAG because that is not a good double barrel card and you called 20 on a fairly dry board so I don't think he's expecting you to fold.

I would've def folded the river.

Limp calling here is begging the the result received. It is playing without a plan totally.

Ya I had to learn the hard way that playing KQ in early position is almost always going to put you in these tough spots. It may be wise to just fold in these spots pre. Limp calling is a leak for sure. You described the V as TAG and most good TAGs are never triple barreling with AK or JJ here which are really the only two hands you are beating.
In the future if you are going to open limp with hands like KQ OOP you are going to have to be prepared to fold when raised. I still think folding UTG is fine if you aren't comfortable in these tough spots. It will save you buy ins in the future.