I personally would use Shane Flipping- Flipping Custom Homes. 

Personally, I'd be very conservative in my revenue projections on something like this just in case this trend continues. 

why no MLS  agents may have done a bunch of your homework up front.. just offer what makes sense to you.. me personally I would start with  the zoning maps and only look at props zoned for the size you want to create.. then work backwards.. no sense chasing deals without knowing the zoning up front.

You need to compare your cost of living, and overall personal cashflow each money with your current situation vs. this potential new acquisition.

Yes you can use zillow/apartments.com/Craiglist, but the most success i have personally would be FB Market place.

I’m not a greedy person in the least bit.

Another thing to consider is that if it was your personal residence, you may be able to exclude some capital gain income if you sell it within a certain amount of time.Best of luck.

I appreciate any insights or personal experiences you can share.

I guess the proxy might be what the person is paying now provided this isn't their first.