My husband texted them to see what happened in the basement and they said there was a small leak in the washer a few weeks ago, but it is now fixed.

I'd be up at night worried about water leaking from a faucet, all those pipes just waiting to break, that old window that is about to start leaking, or pests getting in, or mold, or appliances breaking, or tenants causing damage, losing their job or getting divorced or dying, or a tree falling on the house or sewage backing up into the house or any number of unexpected and expensive things that happen at the least opportune times.

Heat is natural gas.

Gas that car up to get driving toward success(I wont let electric cars ruin this metaphor)!

Interested in hearing some answersI know timber, gas, and mineral rights...Im just not sure how to go about this

However it's zoned as a duplex with the city(has 2 gas meters, 2 furnaces, 2 waterheaters). 

Other non-code enforcement issues I look for when doing inspections on my own: change air filter, check to make sure toilets are not running, run water in sinks and check drain pipes for leaks, check for signs of unauthorized pets, check to make sure all windows operate, check all GFCI outlets with a tester and make sure they reset. 

It also has loose/damaged siding, security bars on windows that need to be removed, earth-to-wood contact in the foundation and siding, leaks in sinks, windows that don't stay open, loose toilets.

I invest out of state so I've wasted a lot of gas checking out properties first only to have my offers be beaten out.

I’d recommend using the credit cards at least minimally, say for gas and or groceries, and pay them off every month (or every week) to show activity.