Jimmie: What I find that really helps is getting a river map of the water you want to fish. Henry's Fork Anglers in Island Park, ID has a very good selection of river maps that show public access points. Henry's Fork Anglers 1 800.788.4479 Mike Lawson Professional Guided Fly Fishing 3340 Hwy 20 Island Park, Idaho 83429
South Fork Outfitters in Swan Valley (on hwy 26 east of Idaho Falls) also has a good selection the last time I was in there. The other thing that helps is the series of books "Flyfishers Guide to Wyoming" or the state of your choice.