I highly suggest adding on Vandalism coverage and make sure you speak with your agent about how the policy coverage works and does not work. 

He spent $5,000 doing that, and suggests a return of $3000/$5000 = 60% annually.This sounds like a great idea- but in practice, I think it would fail miserably.

Title insurance, property taxes/proration, insurance, lender fees, transfer taxes, attorney, title report and update (continuation), filing/recording fees, etc.Look at a typical HUD-1 and you'll see all the lines--there are lots.I would suggest you contact a local title company and get the local low-down on your typical costs.

So before I offer my suggestion I should note that I don't have any first hand experience with this situation nor am I a lawyer or CPA.

Excellent suggestions.

We are doing a remodel on a house in Sunriver, OR.  Most of the homes there were built in the 70's and have an overabundance of wood and volcanic rock everything! The rock is a black and dark gray color, not appealing...

Any suggestions on how we can do the deal now?

I just came across this article from Calculated Risk (the article is about a year old so here is the latest data.) which suggests that MF demand will start to shrink due to increased supply from new building and decreased demand from those aged 25-39, who will make up the top three age brackets in 2020, who will enter their prime home buying years. 

Anyone have suggestions?

I suggest using the name Manufactured Home Community vs Mobile Home Park:)