Now I have found out that she has been visiting a friend in the building and plans to do so more often in the future.Can I ban her from the building?

I run one of the FB pages, there are many of us locals who would be able to give Modesto specific advice.  

This way you get to know the neighborhoods instead of buying area unseen or from just a weekend visit.

The article profiled a California investor who bought online, not only without walking the property but also never having visited Austin.  

I've spoken with a number of realtors, visited various areas, and so I know I can do this.

From a Facebook Page response: I had a house-hack a few years ago and built a custom bar into the house.

IE making sure the kitchen has can openers and a dish drying rack, picking up the mailbox key from the post office, assembling night stands, etc.Most of us manage remotely just fine, but most of us also visit our property once before going live to get it all setup. 

I pay 3% to VRBO and Airbnb, about $1,000 annually in some platform fees, and spend a few dollars for an annual site visit/vacation to the properties.

I visited the property personally (currently his place of residence) and no one was home when I was there. 

My husband just bought a fly fishing rod, and if you don't mind a newbie, I'm sure he'd love to join and chat real estate when you visit!