Few tips from a rookie...
I boot looped my Droid Pro, but on power up if you hold R and M keys down it will boot to some console. You can then press Volume Down and Camera to get to the "Factory restore" screen which will roll you back to 2.2.1.
From there I ran Gingerbreak and it rooted it just fine.
If you run ADB SHELL to access the Droid a first command is often SU to enter super user mode, but you need to make sure you watch the droid screen because it will ask you to confirm allowing SU mode to the shell user. After that you can do whatever you need from ADB.
I do appear to be stuck, with 2.2.1 and can't figure out how to bring it forward. Any additional advice there is appreciated.