Ditch witch so brutal. Plus on 15000 feet the Hand cleaning up of trench sucks.
Would be 6 or 8 inch shovel
Shovel?? 15,000 feet?
I have both a old R-40 4X4 Ditch witch, and a walk behind, both are good machines if run properly, not going too fast can allow for a cleaner trench, I have asphalt chains for both, although a pain to swap out, but I usally charge by the hour since you never know whats in the ground, rocky soil can really slow you down, and soft sand can be a pain as you have to go real slow to get a good clean out, and big rocks or concrete chunks can just flat bring you to a halt real fast, I hit a boulder with the walk behind once that caused the machine to kick back, and it through me about 30' cracking a rib.
Of course trailer parks or other places with a allot of imbedded utilities would mean hand digging or direct bore is about the only way to go.