Best use of 100k for income stream

[Bruce Reeves]

Lot of variables in this question but I'll try to keep it simple. My ability to retire depends of course on an income stream. Current plan is to sell my home and use the equity to pay off my rental property. The duplex rental currently rents for $900/side, so $21,600/yr gross total. I will have other living arrangements, so I do not need to replace my current home with another.

Feel like there may be better choices to use the approx. 100k to create an income stream similar to the duplex. Thinking is, can I use the money to create a similar income and keep the duplex so my tenants will be paying it down for me. Hate to stop other people from creating more wealth for me which is what I feel like I'm doing by paying it off. 

Look at four-plexes? Bread and butter 3/2/2 in my area are around 130k with monthly rent about $1,100, so hard to replace the duplex income with 100k down.

Thanks for any help with my plan which hopefully goes into affect in three years!