Sarah, I know I'm a pest, please don't be angry with me ;-)
Is there any chance to convert the easyflash format of the Briley.CRT to the magic desk format?
This should allow anybody to build an (e)eprom based cartridge (of course this config would require a disk unit to save the game).
In example I was thinking about this project:
https://www.pcbway.com/project/shareproject/Universal_C64_1MB_cartridge.html
Viewing post in Briley Witch Chronicles (C64) comments
You can use my EasyFlash 1CR for that. I designed it more or less with Briley Witch in mind and released it as an open hardware project specifically to allow people to build their own cartridges. But I also sell kits and ready-to-flash cartridges if you don't want to source all components yourself.
No Magic Desk required.