Summer 2000 I did the Northern Tier going East to West. I decided to go to Halifax, Nova Scotia, Canada and bicycle the approx. 700 km from Halifax airport connecting with the Northern Tier just North of Bar Harbor. I never regret that choice and would do it again. You have direct flights from Europe to Halifax with Air Canada. The airport is 30 to 50 km NW of Halifax, it is a small airport and you are in the middle of nature within 500 meters of biking. It is very stressless. Approx 10 km from the airport you have Laurie Provincial Park where you can camp. In terms of hills, the 700 km from Halifax to Bar Harbor is not very demanding - most parts are flat or gently rolling, however as you enter US at Calais it becomes hillier. I stayed mostly on the Transcanada Highway which is a large 2x2 lane highway with very wide shoulders and low traffic.
Comment: When I did the Transamerica going East to West I arrived at Washington Dulles and started biking. All the hassle with domestic flights, rental cars, greyhound, amtrak etc is just too complicated.
PS: I am from Denmark, Europe.
PPS: As far as I know people usually dont have jetlag going from Europe to USA ... only the other way around. I for instance started biking right away and did not need time to adjust.
Lucas