Vasectomy.
We had a three wheeled stroller (small bike size tires) we used on improved trails a lot. It had bicycle brakes on it so it was great. I like the trailer idmt had.
I didn't build one but I do have one I purchased. I like the WSMs I have both the 270 and the 300 and both have taken elk at approximately 400 yards. I have shot plates at 800 yards but I'm not good enough to do that on an animal in hunting conditions. I think there is still ammo available...