My understanding is (i have not seen the finalized track yet) the northern end of the AZBDR is to end relatively close to the southern start of the UTBDR, thus creating a through route.
The IDBDR (maybe ridden this summer? but i'm not privy to that info) southern start will then be near the northern end of the UTBDR and thus create a Mexico to Canada route (AZ>UT>ID) to compliment the CDR http://www.advrider.com/forums/showthread.php?t=763745
You will need a Navajo land permit as this route travels through ALOT of Navajo land. Rob W. has said to me the dirt roads on the Navajo Nation are awesome.