The values can vary widely.Also, when I'm thinking back on it, I've never seen a 55+ park that allows for rentals.You might be able to do a fix and flip in there or do a fix and sell with financing.If you could snag it for $8k, put $10k into it and then sell it for $30k on a 5 years owner contract with 18% interest, it could be a nice little income stream. 

J Scott's Book on Estimating Rehab Costs is a great way to get an understanding of costs (which vary from state to state).

A specific degree like in accounting, chemistry or engineering or a gateway degree to a professional graduate program such as physical therapy has value.

But I could be mistaken and that may vary from lender to lender. 

Usually for an additional equity percentage of 5 to 10% above what they are already getting but it varies deal to deal. 

The terms vary by lender, but 15% down and they finance everything else, up to 70% of ARV.

So just varies.

It seems too that the USDA loan could vary a lot depending on what area you are in.

The answers to these questions could vary depending on where exactly the property is. 

I've also found that even outside of that, the ppsf can vary significantly for similarly renovated properties in the same school district.