FOUND SOLUTIONS:1 - This looked relatively inexpensive, but requires a window in the basement (which may not be present), and is very much DIY:https://www.finehomebuilding.com/2008/09/10/a-dehu...I found 2 - 5 on the following site:  https://www.hunker.com/12002792/how-to-dehumidify-...2 - Placing Charcoal bricks around the basement3 - Filling a bin with rock salt and drilling a few holes allowing for water to drain4 - Buying desiccant's and placing those around the basement5 - Running an electric heater, set no higher than 95 degrees.I really like option 1... but if my basement doesn't have a window, it won't work...

Your obligation is to tell them their is no fix and that if they like they can pay to replace it with a new one.You could also buy a inexpensive one on sale and install it next spring if you are really generous.

Network and get names & numbers to follow up with themAll of these are free/inexpensive to do & can be done immediately.

What are some little "inexpensive" add-on / upgrades can I do to the home help increase the rent while at the same time giving them the security that I am trying to make this place better for them?

I would stick to SE, flights are more inexpensive compare to Midwest something you should factor in most likely at first you might be traveling more than you might like..Best of luck!!!

When EVERYONE we talked to said to plan for $12-15k PER MONTH in expenses to have a nurse spend 30 mins a day with my aunt in a home, I was so baffled!

Let the technicalities on the late fees go, find the best middle ground solution for both of you, and offer her a bonus to find a new place as you'd rather salvage your relationship and it isn't worth having this come between you two.Chalk the loss of fees and possible rent for a move out bonus as a relatively inexpensive lesson learned about renting to family/friends.

In any case, I wonder if a smaller project (say 4 units) that is on the smaller side with square footage can be built comparatively inexpensively.

I apologize in advance for being so new but is buying an inexpensive mobile home in a mobile home park, rehabbing and renting a good or bad method.

Renting a 4 bedroom apartment is pretty inexpensive compared to Boston which is where we live.