In Dolphin, create a virtual SD card image file. Mount it to your PC using a tool like ImDisk or OSFMount.
If the official CTGP-R setup feels too clunky, the community has created distributions specifically optimized for emulators: CTGP with Dolphin, why not ? - Wii-Homebrew.com Board
: A massive mod pack containing hundreds of tracks that is generally more compatible with emulators. Wiimm’s Mario Kart Fun