Some advice for newby please!

Since you plan to place your unit permanently on family property - and will need utility hookups anyway, look into park model trailers. They are intended for long-stay living and you can often find one that is roomier, better insulated, and doesn't have stairs up to a bedroom like a fifth wheel. Since you would have to connect a fifth wheel to some kind of sewer/septic and have water and electric anyway, you'll have everything you need for a park model without having to worry about dumping waste tanks. The idea about the "in-law suite" is a good one, too, but that can be expensive. Also don't forget to check on local zoning laws first so you don't go to the trouble and expense of setting something up only to find you are in violation of local ordinances or codes.

Rob