I need title of a movie! Help.?

There's not much to go on cause I saw this film like 4 years ago and I
don't remember much - other than liking it. It's killing me right now
and I can't sleep. I need to find this movie! Here's a very very broad
description (sorry this is all i can remember):

This was an indie film, I'm sure of it. I also remember a short film
in the beginning, a sex scene I believe or there was nudity at least.
In the actual movie there's a bus, and of lots of traveling in it - so
the bus is important in a way. This bus is old and I remember lots of
countryside traveling. Setting in summer or fall, takes place in a
small city. Thats it, a terrible lead I know but I know someone out
there can help. Thanks.