I can't seem to make RoA 3 run on my mac. I was able to get RoA 1 and 2 (GOG versions) working on my mac by installing them using Crossover Games 9.2 and then copying the files from the emulated Windows XP C drive to my Mac desktop. Then I installed and ran them using DOSBox.

However, I can't get RoA3 to run using the same procedure. The install in Crossover goes fine. But, in DOSBox I tried copying the config file dosboxrealms3.conf over the whole of my DOSBox 0.74 config file. Then I edited the autoexec to the right paths and took out the final "exit" command to finally read:

@echo off
mount c ~/RoA3
imgmount d ~/realms3.inst -t iso -fs iso
c:
cls
RIVA

The program begins to load, but then says "No CD-ROM drive installed. Sorry"
The GOG DOSBox config file was from DOSBox 0.72, but I can't get my copy of DOSBox 0.72 to recognize the new config file. Trying to type in the commands one by one in DOSBox 0.72 leads DOSBox to crash after the imgmount line. Any help would be appreciated.

I made a bit of progress (perhaps)

I was able to convert realms3.inst to realms3.toast using the cd burning software Toast 6 Titanium. This allowed me to mount the toast image like this:

imgmount d ~/realms3.toast -t iso -fs iso

However, now when I run DOSbox, it asks me to "Enter the Shadows Over Riva CD". Pressing return or clicking on "Go on" repeats the message.

Another Update. I got it to launch using Crossover Games 9.2 for Mac and changing the intial Graphics Mode. However, now the keyboard does not work.

Yet Another update: I got the keyboard to work by running Crossover Games 9.2 for Mac in Virtual Desktop mode. However, the only screen size I can get is very small.

Okay, finally adjusted the screen size by altering the resolution in my Mac System Preferences. Now combat seems to go very fast and playing with DOSBox CPU cycles and game speed in the options menu in RoA3 don't work very well. Game will even crash if CPU cycles are altered too much.

kudos on not giving up :)