Will manufactured home dealerships except a double wide trade-in that still has a loan balance?

Will manufactured home dealerships except a double wide trade-in that still has a loan balance? 

We own quite a bit of property and my husband never plans on selling it.  It has been in his family for 5 generations.  The sensible thought of building sounds depressing, in a way, to me because I don't want to think that would be the last place I would ever live in.  I know that might sound funny to some people, but that is just how I am.  My husband is not like that.  I like the excitement and possiblity of having a new place every 10 years or so.  Or, at least the opportunity if desired.  I know at some point I would need to stick with the same home so that at retirement we wouldn't have much left to pay on.  Also, would it be smarter to pay as much extra on that loan as possible up until trade in time, or would that be kind of like throwing extra money away?  Maybe I should try to pay it off, then trade it in for as much as possible?  I live in a single wide now and am only going to get the pay-off amount for it at trade-in time.  If even that!  But, I only paid for 5 years on it.  I don't think I would like all the hassle of selling it on my own?  Thanks!