This means renting a room to work for the summer is almost impossible. 

Impossible to say without knowing more specifics. 

Based on our research, it's going to be nearly impossible to cash flow in the area unless I bump up my down payment to ~35-40%. 

Even if you were able to find a lender that could offer 80% of the SF property values (which would be hard to do but not impossible) it still wouldn't provide very much room. 

Without more info on the terms of your lease, exactly what the landlord charged you for, exactly when the new tenant moved in, & the exact terms that were worked out with you & the landlord when the lease was broken it's impossible to provide reliant commentary on the situation.Also worth noting that most leases aren't set up to just allow you to break them without financial penalty so I imagine that may come into play in the convo.

So, some of the most basic concepts/rules are never applied, because they were never understood.Without that understanding of those basics, it is almost impossible to make decisions...unless they fit into a nice package that is the same all the time.I see that here a lot. 

It's almost impossible to vet a company.

You and your wife have to be on the same page financially towards your goals (make sure you consult with her because without her buy it will be almost impossible to be successful)2.

The market I'm in is extremely inflated, and it's nearly impossible to find a duplex here for less than 325K.

They look out of place there and they are.However, those are mostly vacation locations or, are strictly for mobile homes, which we all know are difficult (impossible?)