It's a cash cow on a 15 year note with a great interest rate so we'd really like to leave it alone if possible.

Check the lease in detail to see if there's any clause saying you can give them notice to leave if the property is sold. 

Did they need more of a wake-up call that sooner or later they would have to leave?

This leaves them with a liability rather than an asset.If you find this helpful please vote it up or ask me a question how I can better clarify it.

Hopefully we are able to buy another three homes without putting any additional of our own money into the bank accounts.Road BumpMy boss at my company decided to leave earlier this year in April and wasn’t sure if I was going to have a job after he left.

It's an investment you made in your future so unless it's at a vulgar rate, leave it and keep paying it as is. 

Thanks Richard , your answer gives me  some piece of mind , how soon should I start looking for a place , since you have to sign a lease 14 day after , the lease  has been approved , I am leaving NJ on 07/01/2019.

Now what options does that leave us with?

In a hot market, I would think it's reasonable to expect to find someone willing to pay 80k in a relatively short amount of time, still leaving 60k profit, give or take. 

He accepted, but tacked on another $5000 to leave the property fully furnished for us.