If you can work out a lease option agreement with the seller that gives your 60 days to find, qualify, and place your tenant, you could do the deal pretty easily. 

I would keep the PO Box for my business mail, that way if you decide to do something different with that space, you're not constantly changing your business address, plus I personally do not want my business mail and checks coming to an address where it could easily be stolen or wind up in a nosy tenants box. 

But I assume in SF area you can rent that pretty easily.

I know few spots near medical center area which are not expensive and rental easily. 

You have to either buy cheaper houses that you can easily afford, or make sure that you have enough cash in the bank to cover any vacancies and large repairs.

But if you are looking at a larger than normal down payment or an all cash transaction, it is an area that you will be able to easily fill with quality tenants and have an asset that is likely to increase in value over time.

But if you rearrange rooms for the sake of it you will loose money.

Personally I evaluate all STR as LTR, if they won't at least break even easily then I won't look at them. 

You can easily end up underwater in a year or two if the market tanks.

The surplus currently available at court  registry can easily cover delinquent property taxes.