Beer and wine aside, before you make any decisions you have to determine several other things.
- Who besides yourself is going to be using your bus--Designing for a couple is much different than designing for a family. Trust me when I say this, my wife has very definite ideas from me as to what the minimum level of amenities are required when we are not at home
- When you use your bus--Full season insulation is much more involved than just trying to keep the cool in and the hot out during the summer.
- How you use your bus--going out to the back of beyond to that favorite lake up in the mountains will require different design parameters than if you are never more than a few minutes away from an Interstate highway.
- What you plan to do with your bus--tail gate parties or weekend adventures require a different set of parameters than if you are going to be gone for extended periods of time.
Once you have defined your parameters determining what are the minimum requirements will be a little bit easier.
Specifically, when my wife agreed that getting a travel trailer was a good idea her three basic requirements were that the trailer could not smell, it had to have working A/C, and it had to have a toilet. After using that trailer for three years we upgraded because while the original trailer had met the basic requirement the new basic requirement was much more extensive.
My suggestion to you is once you get your bus home lay out on the floor with tape your pre-conceived ideas for your floor plan. Get some cardboard to put up some fake walls.
A friend of mine had to almost completely redo his conversion because what looked great on paper didn't work once the walls were up and in place.
Good luck and happy trails.