On witch of the swamp that first skip camp just after camp 3 (the first of the two skips in a row) is a normal camp not a leader so it needs to have troops assigned to it. I went with the standard 155s 45r setup for this. I tried the walk past with the right troops for it to see if it would skip but it does intercept.
Also you can put the general a bit further along, just over the river and north from the 3 camp, near the sand part so it's less walking distance for the remainder of the camps.
For the overall requirements (excluding the amount needed for the non-skip camp) it should be 25m not 40m as this is all that's needed for the last tower.