Terry, there is no one answer to this question, as it varries state by state. In many states the homes original personal property title can be switched to a Real Property title (deed) only if the property is on a deeded lot and is installed in such a way that it cannot be easily removed.
In most states this would include a masonry pony wall and the complete removal of all towing equipment such as axels and hitches (the Hitch attachment must be cut off the frame)
I hope this helps
Regards
Gerry