Never ran into this one before so haven't really thought about it. Here's what I would do based on my understanding, let me know if I'm wrong, or if there's a better way.
The assumption for this scenario is that you can hear and be heard by the D tower on the ground.
I would do a normal run-up and hold short of runway and contact the D tower and inform them of my intentions. As I understand it I do not need a TO clearance from them, I just need them to respond to me. (2-way comm) I'll have listened to the tower for awhile and know what's out there and be flying VFR, so same as departing any other non-towered airport really.
The assumption for this scenario is that you can hear and be heard by the D tower on the ground.
I would do a normal run-up and hold short of runway and contact the D tower and inform them of my intentions. As I understand it I do not need a TO clearance from them, I just need them to respond to me. (2-way comm) I'll have listened to the tower for awhile and know what's out there and be flying VFR, so same as departing any other non-towered airport really.