@Jenning Yu Great advice and I like your approach with the 4 unit residential higher value properties!
I did consider that and I looked at dozens of three and four Unit  buildings. Unfortunately , this just might be in the Tampa area, nothing made money or enough money.
Prices have been so high for many years and dumb investors are driving them up further making bad deals based on bad assumptions
I’m exploring this portfolio loan now and will not make any decisions until after I weighing the benefits and risks.
cash out refi per home tends to be expensive in terms of fees and I absolutely hate fees.
If I can combine the loans and keep the principal and interest payments the same and free up 500,000 to $600,000 I can grow at my pace ....I love the fact if you have a line you’re not paying on it until you deploy the money versus cash out refi you’re paying for the money while you look for the next deal... I have strict criteria I don’t like losing money and it takes time for me to find deals
I’m betting you’re going to see a 15 % to 20% correction by the end of next year when the Fed stops printing money and the “lag concept “ has a chance to propagate throughout the broader economy. 
