The caliper must come off with the rear wheel, there is no way around it.
What messes folks up the most when trying to remove the rear wheel: failure to remove the rubber brake hose retaining bracket (running along the right-hand-side stay of the swingarm).
When you remove the bolt that retains the bracket (takes a 8mm socket), you then gain enough "slack" in the rubber brake line to allow the caliper to slide rearward with the rear wheel, enough so the caliper retaining tang clears the retaining slot on the swingarm, allowing you to remove the rear caliper without scratching up the rim paint.
Caliper retaining "slot" located on inside of right-hand-side swingarm:
Caliper "tang" that slides into the swingarm retaining slot:
