Hey Gary,
The Wrecking Crew (Jeff, Chris and I) Have done the lower sections a few times. From Emery Henderson TH to the Doe Peak Access (just off 1-17 & New River Rd) is really not enjoyable on a bike. Alot of wash that is just crap for MTB. BUT if you stage at the Doe Peak Access and hit the BCT from there, its great! You'll get to the Boy Scout Loop (Loops around a mtn) and the West side is double track but the East side is really good singletrack. We have in the past did the left (West) up and the right (East) coming back but next time we'll just take the right as it is all singletrack and better than the double track.
A note on that: it'll be uphill and more techy on the right portion (East)
That loop converges and you have a nice little climb then it'll drop down to a water tank station with some very rocky stuff that is wide but soon turns back into great singletrack. This eventually leads you to the Table Mesa TH and the Little Pan Loop.
Maps:
http://www.bctaz.com/gpage3.html
Trailheads:
http://www.bctaz.com/gpage2.html
We are planning to do the whole enchilada in a nice little epic ride at some point. Should be fun. I find the upper sections of BCT (LPL from Table Mesa) to be a bit more exciting. The lower sections are good though. Each individual section takes about 2.5 to 3 hours to complete.