Do you think kevin and cara slept together in the episode the lake it was never really mentioned in the show.

No. I think all the events of that episode took place during the daytime. at least at the lake.

All the events of that episode takes place during the daytime and right before the sun goes down except the last scene before the episode ends,the last scene where kevin argues with his father about going on a date with a girl he walks out the door mad the next scene he is in the car with cara that was in the night time he is watching a movie with her in the car she lets him touch her breast then they start kissing each other, i have a hard time believing a 15 year old guy touching a girl breast and not sleep with her lol.