This is my build chronicle. I'm starting the thread now so that it can be motivation to get things done. By "now" I mean that I don't have the bus yet.
My family makes cross country treks A LOT. I live in Oregon, my wife is from Illinois. We travel back there generally four times a year. We drive a Corolla and have three children. You can figure it out from there. We also like to camp a lot and Oregon has a lot of good camp grounds. Finally, my wife and I would like to travel the country when we retire and this would be a good start. By the time we retire, I should have a 50 year old bus.
Most reliable engine, DT466 or 530, possibly a Cummins 8.3
Most reliable tranny, Allison MD3060 or something (overdrive enabled).
Full belly cargo build
Solar Panels (eventually)
Engine driven air conditioning (it's just nasty in the central time zone)
Air ride (preferred)
100 gallon fuel tank (Preferred, two would be even better)
Something like what Vlad is doing only without the slideouts.