Sounds like you plan to live in one spot permanently. You might want to look at "park models" which are designed to stay in one place but can be moved, assuming you have permitted hookups for water, electric and sewage on the property.
An RV is designed for frequent highway travel so there are costs and compromises. The electricity cost of heat and cooling in any type RV also could be higher than in a building. And if anything breaks down (toilet, slide out room, window, fridge, etc) the cost of parts, repair or replacement is generally quite high for an RV compared to a building.
