You cannot beat the power of an ADU for peace of mind, leveraging your home to pay less monthly and reduce your expenses and give you the experience and confidence of doing constriction, getting permits and working with the city and managing a very easy rental.

What happens when you add purchasing power into a product shortage environment?

RE's super power is equity over time.

Equity is it's chief super power. 

Partnerships equal rocket ships.

I looked at something similar about a decade ago which was some camping log homes in upstate maine which was a beautiful place but the place did not have power (only generator) and heat was via fireplaces.

If you're investing out-of-state, you're really going to want the buying power and reserve cushion that 100K gives you.

One tool I already have is PropStream, which I know can be incredibly powerful.

While there are some rather light legal and tax aspects, buying or selling a note is not rocket science.The hard part is selecting the right note and obtaining the right or an acceptable price.

If you co-sign, the loan will consider both your incomes but also both credit scores, so her credit could impact the terms or buying power.