c.s.carnevale: Specifically, I would like to play Ultima 7: The Complete Edition , which says it requires OS X 10.6.8+ and an Intel processor. I am also interested in Total Annihilation: Commander's Pack, Sid Meier's Alpha Centauri, and Sid Meier's Colonization, but Ultima 7 is the real priority.
Ultima 7 is just the dos game in a boxer package. If you can get boxer to work on your rig, you should have no problem getting it to work - either by using the mac download (which just runs it in boxer) or installing the windows download in wine, then moving it to boxer (which is what I used to do before gog supported mac games).
I had some issues with getting the Total Annihilation to work on my mac. I think you will need wine rather than dosbox for that. I had a lot of screen flicker with the gog package. I ended up creating my own wine package and running it in there (or you could try the one from paul the tall).
I think Alpha Centauri is wine as well.
99.9% sure colonisation is a dosbox game (has the file dosbox preferences.conf in the package).