Remember, the notion of amassing wealth without investing is a dangerous myth perpetuated by self-proclaimed experts.

How do I design a small yet effective real estate portfolio?

The cost of that trip would effectively be included in my purchase price.

@Sushil IyerWith my experience, to analyze properties effectively, you can start with resources like MLS listings, Crexi/Loopnet, tax assessor websites, or paid tools like Costar and Reonomy.

Save for future expenses, especially if self-employed6.

Avoidable and more cost effective if using a broker you like. 

I was mainly thinking about the effects of putting an entire strong cashflow back into the mortgage.

You either have to have paid off properties, own properties in high appreciation locations that you have owned for 10-ish years, or several short term rentals that you self manage (which is a bit of a job in and of itself). 

And asking an agent to run comps on 50 properties a day isn't effective.

It's a type of house hacking that's very effective to get your foot into the real estate investing door.