Hi Hawsey - good to hear from you.
Good to hear too that there is still some CBers active. Is this is in Northumberland ? I wonder if they use CB lingo, like the glory days of 70's and early 80's CB ?
My two passions in radio are data modes and low power portable operation. Back in the mid 80s I'd walk up the Cleveland Hills with a legal uk CB rig, 5/8 wave home made dipole (designed by another good buddy and long time radio ham, who encouraged and helped me to get licenced) , that could be pegged into the hill side and was self supporting, and a pack of 10 D cell NiCd 4AH batteries. I could operate for maybe 8-10 hours. I had contacts with most of the North East England coast north of Cleveland. Had a few contacts into the Cheviot Hills too. Don't recall having much over to the west and the Pennines. But it was super busy. Never short of contacts. And this was line of sight contacts, as far as I was aware. I joined the local CB club so I could use their PO Box for QSL cards. When I went to collect, the QSL managers' children treated me like a star because I'd received so many cards. They obviously enjoyed all the cards too. Great days...
I've done a bit more searching and come up with a few items that may be of interest :
Looks like there are some people doing data on CB :
http://www.transmission1.net/viewtopic.php?t=43866
Useful to know and is probably the reason why the RTTY I did wiped out the band :
https://www.tapr.org/~n5eg/index_files/Page360.htm
Some discussion and solutions to the issue of interfacing a sound card to a rigs microphone and speaker socket :
http://www.iw5edi.com/ham-radio-referen ... 1-and-sstv
http://www.w0btu.com/digital_modes.html
https://m0ukd.com/homebrew/rig-to-soundcard-interface/
http://www.g4ilo.com/usblink.html
http://www.m0pzt.com/datamodes-interfac ... -and-rtty/
https://www.youtube.com/watch?v=FHshPd52l-w
https://www.ebay.co.uk/itm/Psk-31-EASY- ... 0896968460
Exactly what is best will depend on the equipment you use. I don't fully understand the issues, but maybe the links above will shed some light on what the issues are so you could experiment and find the best solution.
For data modes that are not that fast, you can listen to them and they will have a certain sound when being sent well. Just like good morse code has a certain sound.
If you'd like to use your CB's you could try initially using low power and a dummy load instead of an aerial. Your transmission will barely get out of the house, but would enable you to test tx/rx, the interfaces and software.
I suggested a pair of PMR 446 walkies as they are low power and are cheap.
I have a few of the Baufang radios. I'm really impressed by them. If your not a ham I think it would be illegal to use (transmit with) them, but not so to buy or posess them. You could use them in the PMR 446 band, but they are not specifically made for that. Of course you can use them to listen around. Some models of the chinese radios are better than others, particularly with receive selectivity and sensitivity. Don't expect a lot with the supplied aerials. Try using an external band specific aerial.
You should check out the organisation RAYNET :
https://www.raynet-uk.net/
the situation you describe is what they're set up to do. I've been involved in a big RAYNET event which provided communications for a long distance 2 day overnight fell walk/run through the North Yorks Moors. It was a great event and an amazing experience. Never been involved in anything like it before or seen the coordination of so many people.
Not long after I was licenced the Lockerbie disaster occurred. Many of the local hams who were involved with RAYNET went up to help with communications and the search.
Amateur Radio is all about experimenting and tinkering and has quite a social side. So with what you've talked about here, I think there is a great fit. There's always some really amazing stuff being done.
My next goal is to get back up to speed with morse and improve further. I'd like to go and activate(low power portable) a few remote places whilst I still may be able to.
HTH