EstlCAM is a lightweight, low-cost CAM software that runs as a single .exe file. You can put it on a USB stick. It supports GRBL and Mach3 natively and costs ~$60. It lacks ArtCAM's artistic 3D relief sculpting, but for 2.5D carving, it's superior.
: The original 2008 version has very modest requirements compared to modern software, needing only 1GB of RAM and a 2GHz processor. The "Portable" Aspect artcam 2008 portable