Welcome to iRV2.
basically you can get a screwed and glued wood construction , all steel frame or an aluminum frame. Insulation is fiberglass or a rigid foam. Enclosed under belly or open construction.
Interior runs the gambit. Cabinets can be particle board with stapled butt joints, screwed butt joints of mortised and tendon joints. Some use all real wood fronts other plastic covered particle board.
To see how some are built, take along a flash light and pullout some drawers and look around. The plumbing should be neatly bundled and well secured. The wiring should be neatly bundles, tagged and secured. Any wall or floor penetration should be neat and edges covered to prevent chafing.
Call cabinet joints and doors should be neat, not gaps and aligned parallel or perpendicular. The rubber or Dicor roof should be flat and no bubbles.
The laminated sidewalls should be flat and straight...no bubbles.
For full timing you will want a true 4-season RV with enclosed basement, two A/C units, 50 amp service, probably dual pane windows, and all wood cabinets. Typical full time units would be Select, Design or Mobil Suites, NuWa, Teton, King of the Road. These units will MSRP over $100K.
Now there a lots of folks full timing in lesser units by Jayco, Cardinal and other similar trailers.
Have fun looking.
Amateur Radio Operator (KE5DFR)|Full-Time! - 2012 6.7L Ford Crew Cab Dually -2013 HitchHiker Champagne 38RLRSB - Travel with one Standard Schnauzer and one small Timneh African Gray Parrot