I made 2 trips last year from Seattle to Anchorage, driving. One in April, other in mid May.
The weather is a******shoot. I only had about 300 mi in the snow on the April trip and none in May, but it was just lucky timing. While we were on the ferry in May, SE AK had a huge snow storm that was mostly gone by the time we went through.
As said, all parks, state and fed are closed until May 1. All sewer dump stations even public ones in town are closed as well until May. We camped in Denali in April. Free camping, kinda locals benefit. It was awesome but cold at night and the state is brown until mid May at the earliest before there's leaves and grass growing.
Whatever happened to buying a RV in the states and selling it when you're done? That would be the best way not to spend a fortune on RV rent.