Man, this certainly turned into one very convoluted issue for mere mortals like myself
. The pi is definitely out as I haven't got any clue about it (well never say never but it appears like a big hill to climb at the moment).
I like the idea of running GPSD directly on the router so that will be my first way to try and solve this. I have never flashed a router nor used any of the OpenWRT stuff so this is looking daunting at the moment. I will try to muddle my way through it.
Thank you for the list of Asus routers and the software
to go with them - a great start and I like the idea that the software
is set up for specific routers which likely means an easier install.
So much to learn .....