As stated before, check with the tour organizer, they should have some suggestions. Washable and versatile are the key. Think layers. I've travelled to somewhere it should have been warm, but they had a cold snap. Put on nearly everything I brought and got out riding.

That said, you list MN in your profile. Are you at all fair skinned? If so, I'd be considering a long-sleeved SPF jersey and a pair of light weight knickers in case your sunscreen fails you. Whenever I bike travel, I always pack the long-sleve and knickers. About 1 trip in 3 I need to engage the cloth "sunscreen".