Keep in mind, the protection level is greater for you when you're on AD orders. If you get sick, flight doc is an easy call.

And, at least for AFRC, you can depart on IDT, but, you can't accomplish IDT overseas.

AFMAN 36-8001 4.2.7 has the details.

http://www.e-publishing.af.mil/share...AFRCSUP1_I.pdf