If you fly over grass, bring along a large screwdriver. Shove it into the ground at the place you'll be when you release for takeoff.
After landing, hang the handle on the screwdriver handle. Walk to the model and lift it and the lines clear of the ground. Walk the model back to the stooge with enough tension on the lines to keep them off the ground. Then walk the lines to unwrap twists and inspect condition.
To be sure you stay clear of the screwdriver and the stooge, set the stooge several feet out from where you want the center to be while you fly. Move back to that center in the first lap or so.
A large screwdriver handle is also a good marker to help you stay centered without wandering, as is too easy on an unmarked field.
Over unmarked, paved fields I have marked the stooge's handle position with a claw hammer in a rag. Similar to the big screwdriver, but not as solid when you walk the model back to the stooge. (Unless the owner might object, you can paint an 'X' with fuel where you want either the flying or launching center.) Many ad hoc fields are unpopulated parking lots, with painted parking slots - select an intersection of those lines if they're there.