Until the lease ends and then the legal notice time in your market has passed.

For those who have or had section 8 investments (especially in my market) how would you describe your experience?

Use a buyer's agent that knows the market, contracts, negotiations, etc.If you really want to learn about investing, get a job in property management. 

The STR market here has become way more saturated and competitive especially in San Juan. 

All indications here are of a pretty healthy market. 

Two properties available in the highly sought-after Gresham Park area—one on-market, one off-market.

So it could take a decade to get to todays market rent. 2) it’s almost impossible if not impossible to non-renew a tenant, especially if you’re not an owner occupant. 3) As a seller, even if I could remove paying tenants I never would without a non-refundable payment from a potential buyer that covers all vacancies for 6 months if they fail to complete the purchase. 4) You MIGHT say as a buyer that’s worth it.

You could put most of your funds in the stock market and access them when needed for a HML.

What strategies have worked best for marketing midterm rentals in secondary or smaller markets like Portsmouth?

.: Quote from @Don Solt: Hi folks, As the topic states I'm looking to learn everything I can about the City of Philadelphia and its real-estate market.