We drove our truck with FWC camper to/from Anchorage in 2018 (something like 65 days) and we took the ferry to Whittier (with stops in Ketchikan, and Juneau) and drove back in 2021 going through Jasper, Banff, Wyoming , Iowa and then Colorado and home to California (82 days).
I am glad we had 220 Ah (110 Ah usable) of battery and the 200 W of solar in 2018 and happier that we had a 360 w solar panel in 2021. Both trips had multiple days of heavy cloud cover and rain. While a number of camping locations had power many did not. We never had to run our batteries below 50% SOC on either trip but on the 2018 trip I had to manage the electrical use closely. On the 2021 trip we always had plenty of power.