Ok. I have recorded an acoustic guitar without a click. I have established the tempo map via melodyne. Now what? How do I use this new info? If I recorded a drum track using AD2, how do I get the drum track to keep in sync with the acoustic guitar/tempo map? Is that possible? Do I simply quantize the drums and it follows the tempo map and stays in sync? I'm sure this feature is great. I just don't know how to use it. Any tips most appreciated.

Take a look at this thread (which references other threads)...
 
http://forum.cakewalk.com/FindPost/3400319
 

There is a cakeTV video on just this process using a vsti drum.
 
I played along with my guitar track using midi drums then quarantined the drum midi to tighten

Once a tempo map has been created, the timeline will be set to the audio track used, so MIDI will then be lined up with the audio. MIDI inserted/recorded in a track will be to the timeline (so yes, can you can quantize).
 
For AD2, there is also a button on the "Beats" tab in the lower right that you will want to enable called "Synch tempo" which will force AD2 to follow the host tempo (which you want). If that is not enabled, any beats you use internally in AD2 will playback at their recorded tempo. This applies to MIDI played internally by AD2's own audio engine (i.e., the "Beats" tab).