You have a great plan- stick to it. Yes it's very easy to leverage your money and own more property. However when you leverage you also create risk for yourself. So you have to determine if risk is something you want to live with.
Let's say instead of owning 2 properties in cash you leverage your money and own 4 properties with a mortgage. Well now let's say that all of your vacancies in these properties come up at one time. That means you have to pay 4 mortgages, holding costs, taxes, etc. on 4 properties. Now that will make you lose sleep at night.
If you stuck with your plan of owning 2 in cash and they both go vacant- well you don't owe a bank anything. No worries
Like one of the gentleman said above if you're going to leverage your money and still want peace of mind, find a mentor who has done this successfully and can help guide you through the process.
Couple pointers if you're going to leverage
1- Don't buy property that is older and will have big maintenance issues. Replace the plumbing, electrical, roofs and HVACS's up front. This isn't very expensive and is worth the cost up front. I've had pipes crack in my properties and had to spend 2 years worth of cash flow to fix the damage- it's worth 3-4k up front to replace the plumbing and have peace of mind. Calling out an electrician at $100 a pop becomes expensive if you've got problems with the electrical. I suggest buying properties built in 1997 and later.
2- Save! Set aside 200-300 dollars a month on top of your normal savings for vacancy and regular bills. This will give you peace of mind and prepare you for tenants moving out, evictions, repairs, etc.