I vaguely remember this but I will try to fill you in.

Guy loses his virginity to his girlfriend right after graduation in his RV and then she leaves the next day or so and goes to Canada(I think Canada anyway) and be a model. Then him and his friends go to find his girlfriend taking the RV. A bunch of stuff happens along the way, like them car surfing on the rv and some cop was following them the whole time as well, and I believe they put sugar in his gas tank or maybe it was vice versa. The cop was actually a private investigator his parents hired to follow them. He lived somewhere on a beach. I think his parents owned a surf shop on the beach. I also think that their rv or another vehicle got stuck on train tracks and was hit by a train.

I think that is all one movie and I am not confusing two different movies.

Any help is greatly appreciated.

Year was eitther very late 90's or early 2000's.

National Lampoon's Going the Distance: Going the Distance (2004) - IMDb

I couldn't think of it for anything and it was driving me crazy and I couldn't get Google to recognize anything I was trying to search.

Thanks again!

You are more than welcome, Adam. :)

It's a fun movie and I probably would have had more problems thinking of it if it weren't on the shelf in front of me. :D

Haha, well I'm glad someone was able to help me. I am thinking it was a pretty good movie and may be worth a watch soon.