Honestly get there early, park at the gateway and walk down Thames as far as you can get. The hike back is worth the hassle. The local radio station WADK does parade coverage so if you want to pop the listen live on and jump into a coffee house or something you can get a pretty good idea of how long you have before the parade gets close to you. I used to have family who lived near Thames Street Glass, which is not far from the grandstand at the end of the parade route so you ended up with the various drum and fife/ drill teams and other stuff getting to stop and handle a bit of performance for you sometimes.