We went up the summer of 2015. We left W. PA the first week of June, spent a few days in Calgary, then on to Alaska via Banff and Jasper NPs. We returned via the Alaskan Ferry from Juneau to Bellingham WA the first week of August. The weather was great the whole trip, and had no bug problems at all. I think the posts provided so far are on target and I would add only a couple of points.
If going up the Alaska highway, make sure to carry enough food and water for four days, for everyone on board. The highway can close due to fires, floods (this summer), or other reasons and you are stuck with no where to go, until it reopens. Don't let this stop you from the trip. Just plan for it.
Remember that July 1 is a holiday in Canada, so campgrounds tend to fill up. If traveling in Canada on this day, it would be wise to make reservations in advance.
Have a great trip.
