It gives additional Liability coverage if the limits of your homeowners or auto policy is exhausted. 

We always recommend that borrowers exhaust the conventional financing options first because the money is cheaper and the terms are better. 

For the most part, there is no income verification (although you'll need the operating income statement and the leases for the property).The first choice should be local banks and credit unions, then conventional/commercial lenders for loans over a million, but if you've exhausted those options, a portfolio lender will be able to help. 

Since you've owned that property for so long you've exhausted the depreciation allowance and your basis is probably close to zero. 

We always recommend exhausting your conventional financing before going portfolio, but if you don't qualify for one reason or another, portfolio works too.Hope that helpsStephanie

@Susan Ali I would start with installing ceiling exhaust fans they wire in fairly simple. 2nd I would remove the water damaged area and see if there is any moisture damage above it indicating a leak from up stairs.

You will be wanting to sleep in after an exhausting week of day-time work followed by night-time renovations and they'll be pounding on your door at 7 AM Saturday morning to let you know they are moving out next week because (reason X)...All of those things still happen with REGULAR rentals, but they don't come at you from the next wall over or your front door. 

You'll see the fire-risk electrical panels, slab foundations issues, ungrounded electrical, aluminum wires, exhaust venting into attic, badly graded lots,   etc. and it will eventually not scare you as much. 

I had a big issue with a tenant regarding basement dampness and it was costly and mentally exhausting.

I am not in that area, but you might try and contact some of the owners listing on AirBNB and VRBO as well as the euro specific companies like Wimdu, HolidayLettings, Clickstay, OwnersDirect, or 9Flats.That is not an exhaustive list so do some research.