The answer is to value this as any other business generating income, not just stick within the confined box of valuing the real estate only.  

They had no interest in the mobile home; they just wanted the property so another family member could build a home on it.

I own a unique mobile home park in South Carolina that's relatively small (5 acres) comprised of 12 lots (I own 8 of the homes while the other 4 are owner-occupied and charged lot rent) along with a house (3 units). 

Ugin,When you say permanent foundation it is required by Fannie Mae, FHA, VA and Freddie Mac that a manufactured home/Mobile Home be on a permanent foundation. 

The price points here are a little high, if you don't go for a 55+ community/mobile home property. 

Purchase price: $82,077 Cash invested: $50,000 Sale price: $275,000 Fix & Flip mobile home with extra lot.

Hope you get a mobile home expert to help you out. 

@Tyler Cobb Yes, mobile home investing can definitely work.

My STR had 15 Mbps, and I could stream Netflix on four TVs and a mobile device without any lag.

Personally, I'm very conservative, and I confine myself to sponsors that have a track record of at least one full real estate cycle with either little or no investor money lost.