Pick a convenient "Set Heading Point" somewhere in the local area which you know you can "wing it" to without looking at the map. Start the plan from this point.
Subject to local restrictions follow the circuit in plan (but keep climbing to initial altitude) and leave at the end of one of the circuit legs (i.e. upwind, downwind, base leg). Of course once you're above 2,000 ft AAL and/or outside the lateral dimensions of the ATZ then you are clear of same and can do what you like.
For me the concept of setting course overhead the airfield is from the days of flying non radio Tiger Moths (not that I have anything against this!) and as has been said above many airfields don't want you to do this anyway.