In the basement, the casings might be swollen.I'd graphite the crank, and check around the window for excess layers of paint.You may have to do some slight sanding around the windows.You can lubricate double hung windows with bees wax.

Also, it is wise to take up all the existing tack strip since it is a wood product that absorbs moisture and can potentially cause problems if not removed.

The property needs some foundation/moisture mitigation work, a trash out, and a full rehab.

Read the EPA booklet "A Brief Guide to Mold, Moisture, and Your Home."  2.

If you're prioritizing repairs, moisture invasion is top of the list since it doesn't get cheaper by putting it off.If you can do the repairs (especially stuff like major plumbing) it's better/quicker if you can handle the lost income.

The particle board under the plastic coating does not stand up to moisture, so its important to keep the plastic like covering intact. 

"moisture damage and/or wood rot".

Now obviously you could argue other costs could go up too, like taxes, however, taxes are tied to property value, so if the value is increasing then I am creating additional equity in excess of the loan paydown, and therefore could sell or refi and take out additional capital at a later date.

It had a moisture content level in the crawlspace of higher than 20%.

And most importantly, any excess is considered income, not a pro-rated portion.