J.P.
I went to Tanglewood last year. ( I'm the one Kim C. mentioned )
There were alot of people there but it wasn't too bad. They have you park in a big field & you watch the fireworks in the area in front or side of your vehicle. We had enough room to set up our blanket & chairs, others had those shade tents & set up their grills. If you want to do all that go early so you can set up a spot next to your vehicle so you'll have room. There was no activities for the children at all so I would suggest bringing plenty of stuff for your little boy to do or just picking somewhere else to go. There is a pool there but not within walking distance, so you will have to move your vehicle & loose your spot.
I think this year we might go to a park that has alot more going on because the kids were pretty bored last year.
We haven't figured out where we are going yet.