Thanks for the response. On the Boston Marathon they have a list of partner hotels that have shuttles from the hotel to the start of the race. This is in addition to the shuttles from the Commons. Unfortunately most of these hotels and the ones downtown are out of our price range, not Surly 1% here. Sounds like I either need to stay at one of the hotels listed on the website or get her to the Boston Commons shuttles.
As far as actually seeing her on the course I am now planning on trying to see her 3 times if possible. She will likely run the race in 3 hours 15 minutes, maybe a little slower since Boston is harder. So my plan is to be close to the start, around the middle and then get as close to the finish line as I can, will also have our 2 younger kids with me. Some of her friends are going to so they may spread out some or just stay with me. I will have a rental car but the train is probably a better idea for getting around.