Tear apart my initial estimating strategy. Help me learn please

[Jarid T. Sox]

This is a bit of a dual post between a new member introduction and starting out. My name is Jarid Sox. I am currently active duty in the USMC but will be transitioning out within the next several months. I have been listening to the BP podcasts during my commute and have read a few books including the book on Rental Property Investing by @Brandon Turner. I am moving to Montana after a get out of the military and am looking to invest in real estate through house hacking and buy and hold investing. I will be using a combination of VA loans and conventional loans to get started with multi-family residential and eventually multi-family commercial properties. I have a fair amount carpentry and DIY skills and a pretty robust inventory of tools to start with coupled with roughly 60k in capitol to start with. I am waiting until I am in the town that I am moving to actually pull the trigger on my first deal but I am trying to evaluate the market and find deals now. I am looking to get some advice and updates to my strategy.

Currently I am finding properties that have been on the market for a while and getting what they are renting for. I then run the numbers not for what the asking price is but what I can offer to make them follow the 2% rule, as well as 1.75% and 1.5%. I'm using 50% of the monthly total at 100% occupancy to account for expenses. Then, from the remainder I subtract mortgage, tax, and insurance. I'm planning on 20% down and calculate rough cash on cash ROIs from that. So far I have found 3 properties that I think I would have a fair chance of getting offers accepted on. One 4-plex, one 5-plex, and one 14-plex apartment complex. The lowest cash on cash in my figures for these 3 properties comes in at 12.7 with the way I am calculating. 

Does this sound like a fairly accurate way to calculate my initial deal or would you be factoring in other things as well? I understand that 50% for expenses is a very rough number and will vary depending on the property but it seemed to be a relatively conservative approach to start with until I come to know my market better. Any feedback is greatly appreciated!