The portage trails around Great Works and Basin Mills rapids are both on the east side of the river and can also be accessed from the road. I am not yet familiar with these trails or the road access points, but the interactive map at www.isaac26.com/new2.html is very helpful.
The Great Works rapid is probably the best vantage point to watch the races. If the water remains low, you may be able to trverse across shallower parts of the river (as the photographer did last week) to get closer to the action.
on the Bradley side of the river at Great Works there is a good viewing point-when it is low you can scramble out and stand on top of a large crib. If you look at Isaacs map, where the car park is marked
I think the answer really depends on how much hiking/bushwhacking/wading you are willing to do. Not that many really good and easily accessible places exist. On the left side of Great Works there is a nice overlook off of the dirt road (it can also be used as a put in for running the left side), however due to the low water the majority of racers will probably go down the right side. The right side is not accessible due to the mill (unless they worked out a deal where they open up the gated mill road for the races). At Basin (right side) there used to be a path down to the rapids but now you would have climb over downed trees and hike over the far right channel (entirely dried up) to see anything. At Veazie you can park along the road and hike down to the rapids and get a pretty good view. There is also an overlook in Veazie that has a good view of the river (although not the whitewater). The river is also so low you could take a boat out and climb onto one of the many rocks sticking out to get an even better view. I've put all the closest access points to the major rapids along with viewing locations on the map (see nationals map post).
