I'll be looking for areas where I can rent the property out to white collar or stable income families who would be paying rent responsibly and not damage the property.Also areas should have cash-flow positive.

A few things you should know about the market, Philadelphia is extremely block by block, my office is in Northern Liberties where there are 600-700k houses, and a short drive north, and your in the drug capital of the city.

I am assuming that there is a serious drop on one or both sides of the driveway.An economical solution would be Eco Blocks.

My fear is that they'll either tear the walls up themselves to deal with it (unlikely, she seems genuinely terrified of mice), or learn to live with it and I'll have 9 months of mouse damage to deal with at the end of the lease. 

Just evicted an tenant that damage a lot inside the house.

Try things like, calling, sending mail, dropping a letter off in the mailbox, getting additional contact info from the city for the property owner.if you have a log of the number of times and ways you have tried to contact the owner, you have grounds to have their insurance pay for any/all damages caused by the tree. 

She was taken advantage of after suffering home damage during Hurricane Harvey (2017) and lost almost all of her savings.

Your best bet is to negotiate an early termination with the tenant, let them use the last month's rent to cover November while they move out and then you can return their deposit (assuming no damages) so they'll have something to get them started on their next place.

Consider Their Maintenance PlanRenovating damaged components or appliances when a problem has worsened costs significantly higher.

Roots can damage water and sewer and the property itself 8.