Yes, RESTORE is the command I'm looking for. Thanks. It might be a good idea to put that in the Readme file.
The emulator is Atari800MacX (http://www.atarimac.com). It works on Altirra (Windows 8-bit emulator). I'm assuming the non-standard ATR size is what causes the problem on Atari800MacX. Hopefully, you can put the game on a standard double density (180K) disk as an option. That should eliminate the problem.
It did work on my XEGS using an Sdrive Max (SIO device that uses Micro SD card) to read the ATR file. I haven't gotten far yet, but it didn't crash when I typed "GO NE" like it did in Atari800MacX.