My wife has a show in a gallery in May. Afterwards we are tentatively thinking of heading north through northern BC and the Yukon. Then taking the ferry from Prince Rupert to Port Hardy and then mosey...
It depends on the weather. We crossed into Canada the third week of May and spent the summer in Alaska. Honestly, we had absolutely no problem with bugs except for a hike on a wooded trail along a river to a waterfall. They were bad there. The Alaska newspaper stated it was the hottest, driest year in a long time. Maybe you'll get luck!