They need to see the chipping paint scraped and the house repainted.

The term "fairly sizable" means absolutely nothing, since I've heard language like that used to describe a shed in the yard with chipping paint.

maybe some fresh baked chocolate chip cookies and a few tickets to a hockey game will coax her to pay her rent .

The house has to be livable and not have a long list of defects like chipping paint, missing handrails, etc.

If the walls are masonry,  I would look to either tear out the old, rotted floor joists and install new ones I the existing pockets,  or if you want to sister the joists,  chip out the brick to enlarge the pockets to accommodate the sister joists.Or is that a rotten oak log the joists are notched into? 

Your new purpose can be spending time and raising your kids, help the poor, build a business, or continue this game of making money and stacking chips.  

I have worse stories, my property manager, Chip, stole $14,000 in security deposits.

Toss it in an a few broad ETFs or if I wanted to be a little more involved, picking a dozen blue chips and a few REITs to get my real estate fix. 

Take chips off the table and reinvest, refinance to pull equity out, or keep payment low (without refinancing) and just ride it out for years to come.Appreciate any insight,Joe

If the buyer wants to chip in another $200 later to upgrade to the next plan, that's their decision and you saved $201.