Myles Standish State Park is located just this side of the Cape Cod canal so your not actually "on the cape". The park is a great staging area for day trips to Plymouth and all its history as well as being and easy bike ride to the upper cape. The park itself is quite large and has several distinct campgrounds within it ,including an excellent dedicated area for groups. Fees are reasonable and in line with other state parks , the bathhouses are sufficient though not all have showers, a shower house is provided in those parts of the campground.