we've done something similar with our networks. 11 sites/networks across europe, each network/site has 3 SSIDs
Corp - internal access, psk based (currently)
BYOD
Guest - psk changed weekly - provided by reception at each site.
PSK for corp has been set the same for each site (looking at getting Enterprise license for System manager to allow access by certificates)
This allows any staff member to travel to any other site and connect automatically to the Corp network.
Works pretty well 🙂