Welcome. Some good advice so far. Personally I would look for fixed bed,plenty insulation,good amount of on board water & waste storage & plenty locker space. Power wise i'd go with good size solar panels plus split charge relay & good size battery bank. Don't be too concerned about size, you'll get used to it over time just be cautious to begin with. Personally i'd prefer too much space rather than being cramped. Get used to wild camp sites to save money, but be prepared to spend on local amenities & water topups etc.Join the forum as a full member for access to the POI maps etc & then get out there & enjoy!!