Well, the *fastest* way from DHS to Le Cellier may be walking, depending on how fast you walk.
The walk from the DHS turnstiles to the International Gateway turnstiles via the Boardwalk pool area is 1.17 miles. Add in another 0.22 miles from the IG to Le Cellier and you have 1.39 miles.
The walk from the closest bus stop at Epcot (not sure where the DHS bus drops off) to Le Cellier is 0.57 miles. So, you have to figure out which would be faster over that difference of 8/10 of a mile. If the bus is sitting there waiting, then the bus would probably be faster. But if you have to wait much at all, walking could be faster. And depending on the time of day, at the Epcot front entrance you may run into a line at bag check and the turnstiles, whereas the IG rarely has much of a line.
You also can weigh which would be the most relaxing. The boat would give you the least amount of walking, but it's also the slowest.
-Rob