NEW VERSION: I cleared some time and got that new version out ASAP.
Turning off cloud saves in GOG Galaxy and make a small change in a .CONF file will stop GOG replacing the SOSARIA.ULT map every time you start play, allowing you to play with the new Sosaria map as intended.
I've included two copies of EXODUS.BIN now, one for the 'vanilla' game as found on GOG, and another for those use the Ultima Upgrade Patch as they are apparently slightly different. Those of you not using the upgrade patch will have found the game to hang when using the EXODUS.BIN in the original release.
The more you know. Many thanks to Fenyx4 for finding these issues and offering solutions.
Please, if you do find any bugs or have any problems installing or getting this scenario to run, let me know. I'm more than happy to problem solve and help you get it running.