I mentioned the caches along a route only as a means to get a list of what's available, to be narrowed down further. That's easy for the inland part. You'll need the most route editing on the coastal route, a person could easily use up 2 weeks driving the coast. There's a hundred methods, use what work for you.
Another worthy stop on Rt 1 and an Earthcache you may already have on your list is
Halfway between the Equator and the North Pole? (GC1770E) by
Northwoods Explorer (3/1) (You'll have to drive back about 3 miles North to log the Earthcache). The marker at this location is the oldest 45th parallel marker in the US, placed there in 1899 at a cost of $8.00!
What you may not know is that there is a neat store 1/4 mile south of the cache that is a great stop. N 44° 59.8163' W 67° 5.2342'