So I had this happen to me today- ATC clears me for an instrument approach to a nontowered airport, and I say I'm going to do a stop-and-go with momentary delay, and then I'll get my clearance on the ground from GCO. They tell me not to worry about it and just get back with them on the go. Problem is, they didn't really give me any climb out instructions. So how am I supposed to do this? Just depart as I feel and start calling them? Is there any requirement for them to give me this clearance? How do people normally takeoff from a nontowered airport while on an IFR flight plan when ATC doesn't give you instructions? Thanks.