Sauvie Island has only one road access point to the island, the Sauvie Island Bridge, which connects to US Highway 30, also known as NW Saint Helens Road. This bridge, built in 1950, is aging and not built to handle the large trucks that must cross it to carry goods, mostly produce, from the island. Inspectors recently discovered cracks in the bridge, which resulted in a temporary lowering of weight limits on trucks, which caused great concern to the local farmers. After emergency repairs completed on February 13, 2002, the weight limit has been raised to previous levels, with a maximum load of 40 U.S. tons. However, the speed limit on trucks and buses has been lowered to 10MPH, and is 20MPH for smaller motor vehicles. While the bridge is currently functional, it was not designed to carry such large loads and will eventually need to be replaced.
Sauvie Island is a very popular destination for local cyclists, due to the low traffic levels, scenic landscape, and generally quiet, pastoral environment. While there is a wide bike lane on NW Saint Helens Road/US Highway 30 extending into the Northwest Industrial District just outside of downtown Portland, the highway is loud and stinky. I recommend going through St. Johns, possibly along Mocks Crest/Willamette Boulevard, to the St. Johns Bridge, and then north along U.S. 30, limiting the stretch traveled along the highway to about 5km.
Sauvie Island can be reached by Tri-Met bus, via route number 17. While the only bus stop on the island is right next to the bridge in the southwest corner of the island, the service is nonetheless impressive for a totally rural destination. Buses serve the island Monday through Saturday, roughly 6am to midnight, with frequencies of about 30 minutes weekday days and about an hour weekday evenings and on Saturday.
As for motor vehicle access, anyone who wants to park within the wildlife refuge areas must have a parking permit, which costs $3/day. These can be obtained at the grocery store immediately to the north (left) of the bridge to the island.
In addition to the famous pumpkins, a large variety of fresh produce is also available for sale on the island, either recently picked or "U-Pick" directly picked by the customer from the fields. Produce available includes lettuce, watermelons, squash, sweet corn, berries of numerous varieties, apricots, and Walla Walla Onions, to name a few. Produce varies seasonally, so it's best to check before you try to get squash in April or strawberries in November.
The numerous small lakes, and the one large lake, Sturgeon Lake, are good destinations for canoeing or kayaking. I have never done this myself, but I have had friends who have enjoyed such activities. Certainly the potential for wildlife viewing and generally placid and scenic nature of the area must be quite attractive.
And finally, a clothing optional beach, Collins Beach, is located along the Columbia River on the northeast part of the island. While the legal status of this beach has been put into question by lawsuits by landowners (which resulted in better policing to ensure that all nudity remains within the clothing optional area) and a fence built to the river by one landowner (this is illegal under Oregon public beach access laws; the fence has been removed), it appears that the beach will remain clothing-optional for the foreseeable future. A number of "normal" beaches are also available along the Columbia, but the clothing optional is among the more popular, including among those who prefer to remain clothed, due to the particularly attractive, sandy beach environment between the river and a forest.