Hi Dan,
I have created an Easel post that will be included in the v1.44a release soon. You should be able to run your machine using a 3rd party G-code "sender" if it's running GRBL, rather than using Easel. I personally use a custom version of grblControl - which is now known as Candle. I had to modify it to have better support for inches but I believe that Candle now has proper inch support, I should really go check it out and find out for myself. There are a lot of other good free programs out there that should work fine too.
The issue you're having pertains exclusively to Easel and not the Carvey. You should be able to run G-code exported with a Mach3/GRBL post on there just not with Easel unless it's formatted in its specific way (which the new Easel post for PixelCNC ensures). The situation with Easel that you'll want to look out for is the fact that it's a 2.5D CAM solution which means that any kind of relief carving etc probably won't load/simulate correctly but it might still be able to send it properly to the machine. I don't know if this is 100% true, I haven't tried loading 3D toolpaths into Easel yet.
Thanks for the feedback! :)
Charlie