We will be leaving Florida mid April and will travel north and west with plans to be in Seattle late May. Visit family there and cross into Canada early June and spend three months on the Alaska port...
A great spring/summer/fall for you! Why don't you go full-time and you can do trips like that year-round. :)
From Seattle, the Sumas, WA crossing into Canada is very easy. We crossed and spent the first night in Hope. There we stocked up on groceries and got some cash at the local bank - the best rate. Hope is a neat little town. The streets are lined with awesome wood carvings and there's even a Japanese garden.