M-n-M: I would anticipate that rte 28A will remain open. The reason it has been closed in the past is the very close proximaty to the Town Beach and the fireworks on the ground. With the Fireworks being shot off from the bay and just outside the "floating bandstand" at that, I would think that vehicular traffic would not be stopped.
BH- Pony Express is indeed very danceable, and the parking lot in front of the bandstand is cordoned off for people to sit as well as dance.
FE: Alton has always had good displays, but I have thought that the Wolfeboro display has been better (longer and more actual fireworks). Last years old home weekend display was a particularly good display IMHO. We have a new company this year and I am excited to see how it all turns out. Look for the 19 foot bowrider with "Upthesaukee" along the side.
TR4: There was a guy that did a really big construction job, and he even found time to rest on the 7th day
but then again, he may have been able to control the weather
. Hope you can make it.