check raising on an uncoordinated board at the 400 nl levels is a big mistake. even an average player at these stakes will smell set and be able to get off their large hands. it would be better to lead out or just call the flop bet in hopes of inducing a pot committing bet on the turn. a set is usually almost invulnerable so you don't need to make your move on the flop in most cases unless the opponent allows it.