I haven't thought as far ahead as looking at potential areas to buy property.

I would both buy a property to get your feet wet and at the same time make a plan to scale.  

Say they sold the properties over 3 year period and could not sell the rentals together as a portfolio.Could they put the money from each sale into a DST then use the total to buy a expensive rental property?

To buy or not in Portland!!!!  

Your investment property - This you could do a 1031 exchange on and buy another property you intend to use for investment. 

If it is, why can't you buy similar properties that you are renting with the money you make.If you get $200,000 annually(split proceeds with the other owner), you should be able to buy almost any type of property.

They send me mailers wanting to buy my properties. 

EXAMPLE: a local HC has a single comcast email address for their entire office - mysteriously, they seem to be always losing emails and asking us to resend multiple times.The good news is they finally increased their max rental amounts a few years ago, so they are now more competitive. 

Quote from @Jaron Walling: @Kane Spangler There's a since of pressure to build or buy RE in your post.

Why would someone buy now and make little money for the chance that the rates will adjust later?