Raising with a UTG limper PF with KTo is not good; you are building a bigger pot with a weak hand.
Checking the flop is preferrable, but betting is not all bad. However, bet smaller, like 150 to 200; fold to the C/R.
I generally agree with this, especially preflop - you should just limp behind here. The flop c-bet (including the size) was fine, though, but you have to give him credit at least for an ace with the minraise absent a read to the contrary, and fold here to his checkraise. On this board, which is very scary and draw heavy, a c-bet of less than half just screams of weakness and you are begging to either be outdrawn or have the pot taken away from you. So, post-flop, if you folded to his checkraise, I think you played it right. Your real mistake was the preflop raise.