Mobile homes are more trouble than they are worth. Have you thought about the septic system you will have to install?
Mobile homes depreciate faster than you may realize.
Most folks who buy a mobile home want to leave it where it is. This is a problem for you as most lenders wnat the home fixed to the property as "real property" not to mention it mus then be the primary residence of the new owenrs. More negatives.
Suggest you talk with some local agents who have worked with these types of transactions and see what all is involved.
Don't mean to rain on your parade. More issues with this than answers.
Christian Realty San Antonio
Probably better to buy a fifth wheel travel trailer or true drivable mobil home versus manufactured home. That way it is easily removable and may retain some value. You should be able to pick up one cheap now. Manufactured home is probably not a good investment. They really aren't probably made to move around much. Maybe you could put one in the corner of the land on 1 acre and rent or sell it after you build the main house.