Keep, refinance, or sell?

[Bill Ward]

Hello, I've done plenty of reading on this and I'm constantly on the fence as what to do with my one and only rental (former residence) property. I'll keep it short to not waste your time:

Purchased in 2010 for $123k, refinance in 2017, 15 yr loan @ 3%. Total PITI is $900. Rent is currently $1,300. Current sale estimate is $170k, possibly up to 190k with this sellers market. Current mortgage balance $80k. ($500 a month goes on the principle)

Reading tells me the investor thing to do is to sell and use the money to buy multiple rentals or cash out refinance to buy one more rental. But I'm really not that gung ho into real estate. (used to date a real estate expert who helped me get into the game). Refinancing to a 30 yr loan increases cash flow to about $700 a month, but I feel like I'm going backwards extending the mortgage on that property. I rented because the numbers worked, my current house would make another good rental if I were to move again (expected cash flow would be 500-700 month). Honestly I think 2 rentals would be my max I'd be interested in managing/handling. Goal was for supplement income in retirement or early retirement (I'm eligible to retire at 50, which is in 14 years).

Part of me wants to sell to capitalize on the value, walk away with 80-100k. But I don't have a plan to re invest that money, I keep hearing equity is dead money, but I also like knowing in 10years it will be paid off and it will cash flow roughly 1200-1400 a month then. I guess part of the problem is not knowing exactly what I want. Like everyone I want maximum money with little effort. My salary is only around $55k currently, I put in $10k a year into my 457b retirement plan. So investing the 100k into a 400k or more property wouldn't be feasible as I wouldn't qualify to pay that kind of loan back. 

If it's paid off in 10 years, cash flows, $1400 a month, does that still look like a waste to someone with more financial knowledge than me? 

Thanks for reading, blunt responses are welcomed. 

Bill