Honey - If you are from the Pac Northwest you will positively melt in the east in July and August. Have you every heard the phrase, "Hot enought to fry an egg on the sidewalk!"? And then there's the humidity. Now if you wanted to cycle the Canadian Maritimes, that would be different. Maybe fly into Boston and connect to Portland, Maine. You do need a passport nowadays, but I'm guessing you already have one if you are from the NW. When the Canadian dollar was a lot less than the US dollar it was O.K. touring in Canada, but now it will be pretty expensive.

Another option you do not mention is the northern Great Lakes. July & August are perfet time to tour - except for the mosquitos. But hey, never can be perfect, right? Maybe fly into Minneapolis - or Amtrak it if you have the time. Direct flights from SeaTac and PDX - also daily Amtrak. DO northern Minnesota, northern Wisconsin, and the Upper Peninsula of Michigan. Drop into the Lower Peninsula and cross Lake Michigan on the Manitowoc ferry to make a big loop. The Apostle Islands and Lake SUperior shoreline are fabulous.

My choice would be the northern Great Lakes.