Landlord is responsible for HOA fees of any sort, not the tenant. 

Honestly, you should have a partnership agreement of some sort documenting how you are going to operate (how to split profits, who has decision authority or how its done, etc.).   

What sort of costs should I expect?

You are sounding very agist and sexist.....Eta: they have lots of work opportunities because that kind of work is needed everywhere - so it would be easy to get a job - kind of like a hair dresser, accountant, etc  

While that's a fine "starting" statement, you need to get down to some sort of brass tacks. 

Vacancy might be a bit higher at that point because a tenant paying that much in rent can typically purchase a property here.. generally, they're saving to move into a house or in some sort of transitional situation.

I am not as scared now because I got the first one sort of over with. 

Unless the company filed a lawsuit, which you haven't mentioned, they no longer have any interest in the property.If they recorded a lis pendens without filing a law suit the penalty against would let her retire in comfort.If they fraudulently filed a lien of some sort but you haven't indicated anything of that nature, again their penalty would be a nice windfall for her.If . . . she thinks that because they had a purchase and sale agreement from some long ago time, she is simply showing that she doesn't understand how things work.Make your offer, open title and escrow, and I'm sure the whole transaction will go smoothly.A title report will reveal anything of concern and a report is usually $50 to $100.

Cameras would be an option but I'd just need some sort of wifi service which we don't have right now.  

If an agent is spending most of their day with retail buyers, then of course you can't expect them to put that sort of time in.That being said, an agent's only resource is his or her time.