For the access issue into the backyard: can't you just add a gate or a door or both?

Will permits or zoning be a major issue and etc.

I agree with @Nathan Gesner that the migrant issue is fueling the fire on the affordable housing crisis, more people needing them has to drive scarcity. 

I also have a limited power of attorney in my contracts to allow me to handle any other issues that arise.

What I often see being a mistake is people ordering a cost segregation study before speaking with their accountant to see if it would benefit them on their return.What a cost segregation study does is analyze a property further to identify assets that be classified with a shorter asset life than 27.5 or 39 years.The issue when getting an 'estimate' from a cost segregation study company is that they are not accountants(more specifically not your accountant).

One of the tenants has been causing issues with other tenants.

I've been deliberating over the same issue (long-term rentals vs. medium-term rentals) and am inclined to invest the extra effort to manage a medium-term rental, given the appealing additional cash flow it promises.

My house is on a corner with an empty lot next door, so it was not an issue for me.

The best part about Reno / Tahoe Nevada are it's landlord friendly, Real estate taxes don’t reassess on the sale, insurance is low and we continue to have increased in migration, jobs (no state income tax) and our own land constraint issues which prevent the market from getting overbuilt. 

If I cashout refi one property , that would resolve my debt issues, but I'm torn.