Alaskan summers are short and busy. Allow a minimum of one day before and one day after your river trip in case of unexpected delays. Plan your cash flow carefully.
ATMs are few and far between.
Choose your gear to be versatile and durable. Soft luggage with backpack or shoulder strap and informal easy-care clothing are best. If you are bringing photo or electronic equipment, invest in a good case or padded bag for protection. Ask Lots of Questions of the outfitters you are considering traveling with. Because of Alaska's permissive business policies, outfitters are not required to have anything more than a business license.