Installing a CRT cartridge image into Retroarch under VICE x64

I have an Action Replay crt image for the C64 and I’m trying to see if it’s fast loader utility will speed up disk access times in loading games into the VICE x64 core. Anyone know how to install it into Retroarch then have it load a C64 rom? I know the crt image works because I can run it like a disk image (ie D64). But I don’t know to keep it resident in Retroarch then load a game rom.