need construction advice for trailer project

[goatherd]

Having herded sheep out of a tent and a traditional sheepwagon in my younger years, I am contemplating a return to the profession, but with goats. Am going to start building a rolling home on a trailer chassis (5th wheel or bumper pull, as yet unbought) and am looking for advice on construction.

My requirements differ somewhat from the traditional tongue-pull sheep wagon, or from many buses and house trucks:

• about 20-24 feet in length to make a more decent living space for more than one person
  
  self contained for parking in town
  
  high ground clearance for very rough roads
  
  reasonably light weight construction, not top heavy
  
  reasonably well insulated
  
  PV power, hand pump water system, wood/solar water heat

any pointers or references would be much appreciated