I use this
remote timer/intervalometer
And this
extension cord It has been long enough for everything I've wanted to do. Mostly I just put my camera outside on a tripod focused on a perch near my bird feeder. When a bird lands on the perch, I trip the shutter from my air conditioned, easy chair "perch" inside the house.
The extension cord is only 33 feet, but I guess you could get two???
I've enjoyed the intervalometer features for quite a few projects. We did some yard work recently and I set up the camera to take a shot every few seconds and then put it together as a movie. Not great, but for a first attempt it was okay. I hope to do more of this when a good opportunity comes up. My sister has a night blooming cactus I hope to capture this way.
Might be cheaper to go the Popper route though.