There are lots of decent, clean, affordable hotels in Syracuse, NY, which is just about half-way between Cleveland and Boston; we used to live in Syracuse, with MIL outside of Cleveland and mom just north of Boston (southern maine, actually!).
Boston... I love that dirty water! Grew up in a small town next to Salem, took classes at MIT while in high school, worked in Kenmore Square for a year. While in high school we spent as much time as humanly possible wandering around Boston! We live in Bangor, ME now but try to get to Boston once a year, if possible. Definitely do the Duck Tour- it's worth every penny, lots of fun, amusing drivers, and really the only way to see the city because the traffic is so horrifying it's not worth trying to drive. GREAT city views from the top of the Prudential Centre, and there's a great shopping mall right in the Center. This is also where Duck Tours leaves from. We love the Aquarium, and hey! Take the water shuttle (part of the mbta system) over to Charlestown to tour the USS Constitution! Great views of the city from the water, and the ship is amazing! Don't forget to go to the Museum of Fine Arts- fascinating and not at all stuffy, really there is something for everyone in the family. The North End is an amazing Little Italy with wonderful, affordable, authentic Italian restaurants and bakeries, and is within walking distance of Faneuil Hall and Quincy Market. Also, Sam Adams brewery is on the T line; brewery tours and free tastings, wahoo!! Last few times we were in town I Pricelined a hotel room; got the Doubletree on the edge of the theatre district (walking distance to Boston Common) for about $50/night for a room with either 1 king or 2 double beds, fridge, coffeemaker. VERY nice, super affordable! WHEW... I will stop and catch my breath... don't get me started about Cambridge, which is just across the Charles from Boston!