It is hard for me to put my Radrover in the back of my 2011 MDX with a huge hatch opening. The fat tires, pedals, and tail heavy bike is not the easiest to handle without banging up your interior in a tight space.
It might fit with the front tires removed. You might also have to look into folding pedals, added quick release on rear tire, and removing the seatpost+ bike seat also?
It might be worth renting a Mustang GT for a day and seeing if the Radrover would fit. You can try trunk storage and maybe a rear rack that hangs off the back as a test. I don't know if a rear hanging rack for a Mustang can handle the Radrover's weight? It would give you time to experiment, order extra parts, and make the mods before your car comes out of storage.
They make trailer hitches for fastback mustangs for about $160. There are a lot of choices for fat tire bikes from Saris, 1UP, Thule, Yakima, etc... in the new or used condition.
Know what they say: "Once you go rack, you never go back".