Hi,
We did the Lund BC to Astoria portion last year and plan to go from Astoria to SF this year. We have also done 3 other Pacific Northwest coastal tours, all starting after Labor Day. As you probably know, living in PDX, the coast can be really foggy during the early and mid-summer months. We plan on leaving about the 1st week in September because the weather is usually a little better, and there seems to be less coastal fog. Another reason for this time of year is that a lot of the schools start classes, so there may be less "vacation" traffic on Highway 101 . The only problem is that a lot of the older RV folks seem to think the same way. We will see how these theories work out. I once did the Oregon Coast the wrong way (south to north) in mid summer, and it was still a great trip.