Other than saving a certain amount from each rent payment (for taxes, insurance, PM, general repairs, maintenance, Cap X, and vacancy), does anyone have a rule of thumb for what a good amount of reserves would be for a SFH or any 1-4 unit property? 

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.

My answers are in ALL CAPS Bold Italics below for better visibility.  

You can change the exit cap rate in the basic assumptions tab cell H67 and see the effect on the IRR and EM in the Equity Waterfall (GP) tab cells V51 and V53.

Not sure how to account for cap ex when you factor cap ex roofs, hvacs, etc in.

A lot of these properties are still trading at low caps, and they have a lot of deferred maintenance.You're seeing a lot of these older properties being traded now.Gino

and would like to do a 1031 exchange to avoid cap gains taxes. 

😎Everything is included for advanced financial metrics as well, such as IRR, Cap Rates, 5-Year Estimated Values, and more! 

How do I know what cap rate to use to find out what the market value of the property is?

You can easily find a turn-key property in the $250k range with cap rates around 6.