First recommendation is don't leave military service (active or Guard/Reserve) prior to getting fixed-wing certified through previously mentioned options (Army RC-12, AF/Navy instructor at primary/advance pilot training base).
Second, if you were to end up in special ops rotors, you would never want to leave. Travel to distant lands, meet wonderful people of exotic cultures, and then kill them. Why quit?
We hired an Army Guard helo pilot into my C-5 reserve unit. He had to attend AF fixed-wing transition (mini-pilot training), then C-5 training, and is now large and in charge flying FRED around the world.