What I do if I don't want to get too sweaty heading over to the YC/BC ( and don't mind if I have to stand on the boat) is wait inside Screen Door where I can see out the windows when the boat is coming toward the dock. Then I just walk to the dock and get on the boat. Since I'm usually among the last to board, I may or may not get a seat, but since I'm getting off the boat at the very next stop, it's not a big deal to me to stand. The only time of year I have been there that this wasn't a viable option was during the Osborne lights season when so many people were trying to board the boats in the evening that they were recommending people walk to the park instead of ride. Since all you are doing is riding across the lake, you should be able to wait in comfort in the shop until you see the boat coming from Epcot and approaching the dock.