I gave her an application and asked for it to be filled out and returned for whoever would be on the lease.

You can rent or lease  a really nice big house in Milpitas for about $4.4k e.g.https://sfbay.craigslist.org/sby/apa/d/large-execu...If the economy really tanks you can move out your Santa Clara tenants and return there.

What type of returns are you trying to hit as well?

Now while she is overseas, she has partnered with me on a rental in my area, so she is getting better returns than putting it in a bank for very little return. 

When you move out, take pictures and send an email to the property manager requesting she return the deposit to your new address at xxx.

We want to house hack a 4 plex, but all the ones we see that might give a decent return are fully rented out.

With my tax situation (higher end of the bracket)  even though properties don't cash flow the calculated returns on the bbt.com investment property calc seem good (considering depreciation) would any of ththe pros ever invest in this scenario knowing that they can cover the negative cash flow.Thanks

QB Reports doesn't generate this for you, but you can easily download their reports into a spreadsheet and add a single line for the initial investment and generate your cash-on-cash return any time.  

If you are in a market with long term growth prospects (and we are), then over the next 10 years or so price appreciation will be a tailwind on the returns of your rental. 

Bay Area appreciation can crush “real estate returns” elsewhere, though you can’t bank on it.