Your profile does not list your lenses, so I will do a little guessing as to what you have....
For landscapes and sunsets, a tripod is obvious. Since you are traveling by car, better to have it and not need it than need it and not have it. A remote release is nice, too.
Since you are looking to travel light/small, I would go with your kit 18-xx lens and something like the 70-300mm VR (or 55-xxx). Landscapes are normally shot at small apertures, and these lenses do well there.
Call your insurance agent and make sure your gear is covered on your home/renter policy.
A post into the landscape forum might give some ideas on where to stop.
---------+---------+---------+---------+---------+ Joseph K Seattle, WA, USA