I am in the same boat as you...I have been nudged in the right directions so far and have not been able to get my gps to function correctly and I believe it may be due to the dcd rom, or rather my ignorance about the GPS. But, the dcd rom I have is rock solid. I love it other than I can figure out how to make the GPS work.
I have:
radio 3.39.10
DCD 3.1.2
with the radio version you had I did not have the best of luck. I am going to try the No2Chem rom now. All your answers about sprint and unlocking can be answered by the following: (Its what another person here has shown me and seems to be right on)
Flashing Guide for beginners:
PLEASE FOLLOW THE GUIDE CAREFULLY~
http://forum.ppcgeeks.com/showthread.php?t=9927
Unlocker:
http://forum.ppcgeeks.com/showthread.php?t=9093
Radio 3.39.10:
http://rapidshare.com/files/113794877/radio339.rar
No2Chem's ROM:
http://forum.ppcgeeks.com/showthread.php?t=25065
JUST REMEMBER, once you put radio 3.39.10 on it and it reboots, DO NOT LET IT RUN CUSTOMIZATIONS. I REPEAT. Once the display says, "customizing in 3 seconds", click the reset button immediately!!!! Otherwise your "sprintized" verizon phone will "convert" to the sprint towers and such!!!
The reason for all that is because Verizon hasn't released a GPS enabling rom quite yet. (and doesn't seem to be planning one) so you have to "sprintize" your verizon phone with the GPS enabling rom (3.39.10) and prevent it from "finishing" it's update. that's all. I"m sure you know what screen I'm talking about. This is the only precaution to the Verizon phones...
I think your biggest problems is old rom and radio also check out the threads at xda for No2chem and back sure you have olipro bl as it will save you lots of headaches