Your fears are justified, mobile homes do tend to depreciate in value. Secondly putting it in an area of lesser homes will also hurt the value of your investment. It never pays to be the nicest home in any neighborhood.
I'd save my money and either look elsewhere for a site or forget mobile homes entirely and look for an existing home. You may also wish to consider a modular which is totally different from mobile home and these do not depreciate as mobile homes do, they maintain their values are directly tied to the market, while mobile homes are more like cars, they depreciate the moment you buy them in nearly every instance.... more