Keep it up man - (awesome to see the mighty Valiant make an appearance

)
This is the start of a good road trip story - just work with the basics - you got the intro down, starting into the buildup. Work out what the confrontation will be, the resolution, and wind down to a conclusion. If you break it down like that you cant go wrong. I'll probably get some 'pro' writers slamming that but it works for me!
The characters are building a good dynamic already (I'm thinking you've borrowed from some mutual freinds here ;D) - I think that can develop to cement the story regardless of happens around them.
Good luck!