I had the pleasure of visiting Caledon Burroughs and seeing how Dr. Goode's duchy fared in the winter months. The snow had fallen, of course, but Dr. Goode had a purpose-built clank to clear the walkways. The little guy had almost finished when I arrived:
When Rhianon visited, she saw the Laboratory in the Sky. It seemed that there was now a Laboratory Under the Sea as well. Would it be accessible with the lake frozen over?
I shimmied down the pole - no high-tech conveyance here! - and indeed the connecting tube went straight through the ice to the laboratory on the floor of the firth.
To accommodate the ice, however, Dr. Goode had installed several vehicles capable of traversing over the frozen firth, including a shuttle to the Caledon mainland and several ice-skimming vehicles.