Two ISP connections and a wireless bridge, probably with VLANs

[chrisberesford]

Hi, I'm hoping to get some advice please:

I currently take advantage of free internet connection at home by using a ~75m wireless bridge consisting of a pair of Ubiquiti NanoStation Loco M5s to link to my family's house with Virgin (cable) connection. This has been increasingly unstable (due to poor ISP service) and at the same time, I'm working from home more often, so more annoying!

There is currently a single-board PC running pfSense at the family's house and both properties are on one big subnet.

I'm happy to cough up the dosh for an internet connection of my own, but I would like it to be from an alternative provider for resilience. I'd like to keep the 5GHz bridge to the cable connection. I would like to set things up so that if either connection fails, both properties can run from the remaining one. Same goes for load balancing - the cable is 150MBps, my new connection would likely be 40MBps. We currently share a plex server and do file sharing between PCs in each house etc and I'd be keen not to lose that, or force it to go over  the internet with a VPN.

I think I need to set up a new pfSense box at my place and instigate some VLANS over the 5GHz bridge. However I'm not really sure of the necessary specifics at all.

Any advice would be much appreciated.

Thanks
Chris