@Dave Meyer is producing great data about this very topic.

You can hope occupancy stays at 100%, but should plan for at least 10% total vacancies (with short term closer to 20% as @Greg Dickerson and I are doing).The other thing you will need to confirm is does 100% vacancy mean there’s a body in 100% of all units (physical vacancy) or you are collecting 100% of expected rents for 100% of the units.

You're probably going to be a lot better off hiring out this work and focusing your time on income producing activities that allow you to use your current skill set.

It is not a way for you to get your hands on the money.Using a self-directed plan to invest in notes can certainly produce better results than leaving those funds in the stock market.Get on the phone with someone who specializes in this field. 

My first place was 50k that is now worth $110,000 and I rent it for $1100 a month so I got a steal with that one...until that special assessment comes...but it has produced a 150% ROI over 4 years so far.

Some put their life savings into buying a home, business, or a income producing property.

An investment produces income a personal home doesn't. 

How long has your rental Ben producing income?

I've also used Top Producer and Seize the market in the past. 

I use mail merge so that it specifically calls them by name and then references their specific property address in the body of the letter.