Purchased home with potential upside in hoping to force appreciation in the house in order to create equity and eventually utilize the equity (HELOC) to begin investing in other properties.

I'm in the process of potentially doing just that. 

I’m stuck when I try to run numbers on a potential deal, how do you generally estimate rehab costs?

If a potential client is using 1031's they will appreciate a realtor they don't have to educate. 

And we're still seeing deals here that are positive cash flowing with lots of potential for appreciation.

Portfolio = Income derived from financial instruments like dividends (including REITs), interest, royalties, and capital gains.Mostly income w/out loss potential, and favorable tax rates.Cap losses may offset cap gains w up to $3,000 loss.

The name of the game is collect monthly premiums and payout as little as possible.

Since you’re looking for landlord-friendly states, consider areas in the Southeast or Midwest, where affordability and cash flow potential are often stronger.I agree.

All that said, and to answer your question, I think a guaranteed check for 66% of the rent offers some peace of mind and limits potential loss. 

Leveraging equity to purchase a short-term rental (STR) in Tampa Bay can diversify your portfolio and potentially generate strong cash flow, but it also increases your financial risk.