In my area I schedule 3-4 showings from noon to 1pm and don't mind if they overlap since it creates a sense of scarcity and urgency.My last rental I had 2 applicants fighting over it since they saw it at almost the same time.

I usually end up getting tenants who want a 2-week to one month overlap of their old lease and mine.

Funnel people to open houses or overlapping appointments.  

Many of the architectural styles overlap, and for most investors on BP they aren't restoring historical homes, but redesigning older homes and updating their looks, adding modern conveniences, etc.

I am overlapping my contractor repainting the place with the open house to shorten the vacancy time.  

Sometimes you can convince them to pay overlapping rents for a couple weeks, but don't expect good tenants to be ready to move in tomorrow, is my point.  

Or are you expecting them to give their 30 days notice, but still pay you for the overlapping 2 weeks?

I do know that they won't pay any overlapping rent, if she moved into another Section 8 unit.Your best bet is to just call the housing authority.  

Obviously, check you local/state laws as they overlap HUDs.

Strategies do overlap from location to location so as you get more versed in real estate investing techniques, you'll be able to find deals in your neck of the woods more easily I would imagine.