They see the lower rent and don't factor in the extra expense. 

At a minimum you can put your extra funds into a high yield savings account, or even better 4-week treasury bills that give you state tax exemption and keeps you liquid for your next acquisition.

Well, do they have a job to pay that extra $200 plus utilities per month?  

We do get a better fee/split structure, and that's a fair trade for the extra work of managing a large investor base and it's associated extra accounting and tax reporting overhead.I also find the advice in the OP to be contradictory. 

Consider how it will be used and if the floor can function as storage, rec room, family room, extra sleeping space, etc.From what you've shared, my concern would be the "hills" that may cause a tripping issue.

Do you have a full-time job already, assuming you have extra time, do you want to spend it doing another brain-draining task or would you rather spend it enjoying yourself?

You can lower the price.The buyer can pay the extra $9k in cash, if they have it.The buyer can walk away with their earnest money and you can lower the price $9k for the next buyer or require them to bring $9k in cash. 

Older people like this often need a little extra help with technology.

If you buy an outdated smaller 2bd/1ba home for $150,000 in an area where remodeled 3bd/2ba homes are selling for $300,000, and you know it will cost $50,000 to update the home and add an extra bedroom and bathroom, you can be relatively sure you will be able to recoup your investment. 

If you need a reliable roofing contact, let me know—I’d be happy to recommend someone.Your agent should have negotiated a clear possession date that accounts for the seller needing extra time to move.