Full Time RVng is rarely less expensive than renting.......
Insurance, registration, electric/water/propane, maintenance PLUS regular living costs usually works out close to S&B housing.
IF you can set up on families property then cost of fuel and campsite could be 'saving' provided you had monies to cover that anyway.
Folks have full timed in every type/size of RV made...........really up to the individual.
Just because a mobile home WAS on family property does NOT mean you can park an RV and live in it. Check city/county/state zoning laws/restrictions FIRST!!!