I see a lot of investors buy good investments, but then they lose tens of thousands because they have no idea how to manage.

I will add that to your question of 10% or 20%, you need to ask yourself whether you need the cashflow or not. 10% down would leave some money with which to buy more properties.

The first thing I want to point out is that it may be wise, in your thinking, to separate the property itself from the STR business that's being run from the property.In the old days (as recent as 10 years ago), people buy a vacation home to enjoy, and they leave it empty when not in use. 

BiggerPockets also has a calculator to analyze deals, and I highly recommend you start this as soon as possible, even if you are not ready to buy.

If you sell for a net sales price of $1 mil and buy for a net purchase price of $700K you will owe tax on the difference of $300K.BP may have a capital gains calculator you can use.  

Is there a buy out plan?

To buy or not in Portland!!!!  

The biggest question you need to ask yourself is if you are doing this to afford a property you otherwise couldn’t afford or to save money period, that will lead to very different conclusions about where/if to buy. 

I purchased my first buy and hold SF rental property last year and turned the property into a student rental as it was very close to a local College.

I've considered going Dave Ramsey and buying a house with cash and upping my budget to $100k in a smaller market, but that would blow almost all my savings, and $100k just doesn't get you much anymore.