other posters have started threads saying they're going to buy STRs for tax savings... and this doesn't make sense to me.  

According to Warren Buffet, Fannie and Freddie really failed because of high-leverage risk-taking in the fixed income arbitrage space, saying:“The portfolios are what really got them into the trouble…the managements of Freddie and Fannie tried to juice up the earnings, basically, because the insurance guaranteed that they were given that mortgage.

You get to harvest the equity tax free.

even if its interest only, id want to pay down principal here and there. seems like sellers would offer this interest only route so they have 0 capital gains tax, but id rather pay down a bit of principal in 7yrs. i see its not required but it should allow for principal paydown in promissary note3) any general advice to look out for on seller financing?

Forming an LLC for your rental property can offer liability protection, but no real tax benefit.

Here are a few strategies that might help:- Leverage Industry Benchmarks: Many investors use a percentage of gross rental income as a quick estimate for operating expenses.

Hey @Scott Trench unfortunately real estate losses (active or passive) will not offset portfolio income from stock sale gains. 

I'd be heavily focused on mitigating that future tax liabilty rather than directly supplementing that income.

If you pay down $100K in loan saving you $1K in monthly costs against rental income, or you invest that $100K in something that generates $1K in net income the result is similar.

Since you are renting out part of your primary residence in Maryland, your main concerns should be liability protection and tax compliance rather than complex asset structures.