I made it up to West Dorset on 7/30 and successfully found the canister. I started my 'whack from the Dorset col, and by picking my spots I was able to climb most of the way up to the West Dorset ridge before hitting some dense stuff. Thankfully it soon gave way to moderately open woods, which aren't too bad as long as you pick your spots. However, they're dense enough that on the out trip I didn't have a good sense of how the ridge proceeded or how much further it was to the true high point. The woods were thick enough that my GPS had trouble getting a good signal. By continuing forward, I found that the ridge arcs slightly to the left, and by keeping at it, I reached what was clearly the highest summit bump (having passed over a lower bump or two en route). Reaching the high point, I found the Nalgene bottle lying on the ground, so I reaffixed it to the tree. It has minor puncture holes all around it's exterior, so it's just a matter of time before rain water leaks in. Thankfully the register was encased in a couple of plastic bags and was still dry.
By the time I had to make the return trip to the Dorset col I was more familiar with what the ridge did, so I knew that going east the ridge would arc a bit to the right. Rather than rely on the GPS, instead I determinedly stayed on top of the ridge until I could see Dorset Peak right in front of me through the trees. Then it was simply a matter of dropping down to the col.