You can take the boat that runs between WL and the Contemporary and then go inside to catch the monorail to the TTC and switch to the Epcot monorail. Or take a bus from WL to the TTC and then catch the Epcot monorail. It's probably shorter to just take a bus from WL to Epcot.
Coming back, just go in reverse, EXCEPT you won't be in time to catch the last boat from CR to WL. (while I love the boats, it's a small, open boat and can get mighty chilly at night in December).
If you return via the MK and catch the boat from there, I believe it runs for ~ an hour after closing. On the nights of
MVMCP, it would be running longer, but not sure if it runs until the very end. We haven't been in December in ~ 6 years, and at that time, the boats stopped at 11 PM, as I recall. The MK - WL/FW boat is big and enclosed, unless they're also using the small ones.
I'd allow a lot of time to get to Epcot if taking the boat to the CR or MK and then 2 monorails, but it's fun.
