Using electron as a internet gateway for photons

I live on a boat where I have (or am) using multiple photons to monitor battery, cabin temps, refrigerator temps, bilge levels etc. Currently they only function when I’m at the dock under shore power where internet and wifi router are powered up by 110v AC. I plan on installing a 12v wifi router so that when I’m away from shore power I can still have a local LAN where devices can communicate. I just purchased an electron with the asset tracker package so I can geofence (among other GPS tasks) the boat. What I’d like to have happen is that when the boat is at the dock and the wifi is enabled the photons will use that but when away from the dock (but still in cell range) the photons can communicate via the photon using it as an internet gateway.
Can this be done? Is there a better / different way to do this?

I would guess that you can hook up the Serial lines and have the Electron always listening for data, process and do stuff.

On the Photon side, it will check for the WiFi status and switch over to sending data over Serial line when WiFi is unavailable.

I would use a 4G WiFi AP instead of the Electron and your 12V WiFi router and do the GPS stuff with another Photon (which also fits into the Asset Tracker Shield).
You'd just need to confirm that the WiFi capabilities (including inter device communication) are kept alive while the cellular network is inaccessable.