I wish I could remember the top three states with mobile homes. I THINK one of them was Indiana (it could have been IL, WI or MI). I was very surprised when I heard this information because I think of mobile homes being more common in warmer weather states. Mobile homes can be listed through the MLS or Realtor.com. I looked up Bloomington IN and went to the advanced search. I checked "mobile homes" and also "add nearby areas" 50 miles and randomly check marked a bunch of cities. My results came up with a home (I don't know the dimensions of a double-wide) on 2.5 acres for $39,500 in Palmyra on one end and $280,000 on 1.42 acres in Zionville. I did the same thing with Durham, NC and came up with 2 acres in Burlington for $85k and $429k for 4 acres in Efland. And then again for Baton Rouge, IL and came up with $48,500 on 1.66 acres in McComb, MS and $160k on 2.7 in Independence, LA.
So, as you can see, you need to narrow it down. I came up with over 300 properties in my random search.
I also did a non-random search and New Bern, NC (which is beautiful) had 2 acres for $16,900 or 1.14 acres on water front in Sea Level, NC for $689,000. (I actually knew the listing agent for the water front property back in the early 1990s.)