Consider renting a car to make the most of your visit and enjoy the scenic drives between cities. Alternatively, take advantage of the public transportation available in Washington, D.C. and Boston. Expect to spend around $400 on transportation costs and approximately 15 hours of travel time throughout the trip.
Be mindful of the weather conditions and pack accordingly, especially for the beach days in Cape Cod. Consider extending the trip by a few more days to fully experience all the attractions and activities available in each location.