There are no special parking arrangements in Rensselaer for Hudson400 River Day (Saturday, June 13th, noon to 5pm). Plan to wear good walking shoes!
There are about 20 spots along 5th Ave. within Riverfront Park (including two handicapped spots). The Riverfront Park entrance is at Broadway and 5th Ave, across from Dunkin Donuts.
Another nearby parking area is further along Broadway, under the highway, on the other side of the ramp from 5th Ave. Also, there is street parking all along Broadway.
Public transportation on Saturdays is limited. You could park at Defreestville Park and Ride and take an hourly CDTA 214 Bus to Amtrak (or take the 214 from Hudson & Broadway in Albany).
The Amtrak station is a 2 block walk to Riverfront Park. From there, the Albany Yacht Club is about a half mile down Broadway, and Fort Crailo is another quarter mile further.
Rensselaer plans a real public bathroom for Riverfront Park in the near future, but be aware that this is it for now. ->
Here's the earlier post with the schedule for River Day - Hudson400 in Rensselaer, as well as a Google Map of the festivities:
View River Day, Rensselaer, NY - June 13, 2009 in a larger map