You would do better to best by checking out this organization.
http://www.unlimitedsdetroit.com/photos.cfm
http://www.unlimitedsdetroit.com/index.cfm
The more they dick around with the web site the less good it gets but the links page has about all worth seeing.
If you join, you get the club magazine ten times a year, and like motorsports, the mag. has declined over the years but it is still about as good as it gets.(And they do cover every race plus some other classes. I.e. GP hydroplane, and other V-8 classes.
The tracks that have the longest history are:
Detroit, MI Chrysler/Jeep APBA Gold Cup
Evansville, IN BUDWEISER Thunder On The Ohio
Madison, IN Madison Regatta
Tri-Cities, WA Budweiser Columbia Cup with Wings
Seattle, WA Texaco Cup at Seafair
They kept on racing even during the nasty recent years.
I was at Evansville when a lap record was set and it is truly cool to watch a big hydroplane whine/whoosh by at 200 mph only thirty some feet away (you can sit on a rock by the water which is even closer, but if you dangle your feet in the water you will be told to stop, OR LEAVE.)
That was fifteen years ago, and from what I have heard they have not yet been over-run by safety nazis.
I attended races at Detroit, Evansville and Madison.
Detroit was marvelous watching qualify from the Roostertail club deck, which was in the river. They came by the deck wall with six feet of clearence, at most, as you looked down at them.(The Roosertail was closed and sold, so I do not know if you can do that anymore) and at Madison, the entire city is a historic site.
(Evansville I was told was hot, and when I was there I found out they were not lying. I actually skipped the races after viewing qualifying, as they do not lap as fast and I had seen what I wanted to see the first day. )
Also, IT WAS HOT!!!!!!!!!!
Those two are the best and from western people I communicated with, the eastern races are better for the fans if for no other reason one can truly get CLOSE to the races.