We are now doing short term rentals but we're thinking about changing to a small wedding venue. 

Hi I'm gege new to the site starting the Wholesale investment and need help finding seller, where should I brand myself is there an email pitch or a call pitch I can send to seller, like people in foreclosure, or bankruptcy, or late payment and where will I get the ARV, Repair Value, Offer The price that you need to get it under contract for and  where do I get the contract form and if I get a seller and a buyer how do I get a legal person to handle all the paper work for closing.

Suggest you go to their site, there is approx 7 videos for you to watch to see if you want to go to the next step. 

Or do you think 100%+ appreciation in <10yrs is "minimal"?????? 

Is it as simple as getting the site designed and engineered for the footprint, cleared and graded (all of which I am comfortable with), and then hiring a GC to build the building?

A new site for NH foreclosure auctions just launched called Bid Pirate, worth investigating.

Most investors make the same rookie mistake: They focus on problems instead of people.
Telling sellers everything wrong with their house and justifying your offer with repair costs doesn’t build trust—it kills it.
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Here are some details, from a non-HUD site and from HUD. 

I've referred so many people to this site.

If you're thinking about selling it, you'll probably be better off selling a vacant then with a tenant.