TP-Link N300 WiFi -> WAN $30.
[Link: amazon.com]

We put in a basic router for the simple Control4 remote system. And carry with us one of these setup for connecting via WiFi to our phones as the hotspot.

For the novice user, they're cheap enough you could set one up for each of her locations and her phone hotspot, and she would just plug the appropriate one into the router of your choice in the RV. Then she'd be behind whatever firewall etc you provided in the router and on her own 'WiFi'.