Offering simply a suggestion that has worked for me pretty well. Since our last trip to BRP I have purchased several frogg toggs about two sets a year due to wear--wind--heat, etc. Anyway, they are relitively inexpensive and I find myself wearing them a lot. They work as a light wind breaker for cool temps, they are breathable so they are not uncomfortable w/respect to warm temps and they are perfect rain gear. I think for such a trip at such a time they would likely cover most if not all the bases. Higher elevation changes you may encounter some thermoclines warm into cool and vice verse, it may be sunny and warm on one ridge, go around a curve and it may be raining on the back side of the same ridge. But, I would like to think by June for the most part there should'nt be any major temp change issues. Available space for such trips is always an issue, the frogg toggs are multi purpose for me and they compress fairly small when put in a freezer bag, just push all the air out and zip-um up. Good luck, its a great bike trip, I find it real hard to go 50 mph on the feejer for long periods