I will be heading out to fish the Missouri from July 12-20. As part of this trip we are going to take a drive down to Yellowstone for a couple of days with the primary objective to fish Slough Creek for a day. I have hiked in for day trips in the 2nd meadow twice, but haven't had a fishing partner in good enough shaped to do the 8+ mile hike (each way) in a day. Has anyone done this? If we start early, I don't see why wouldn't be able to do this. Also, is there anyway to purchase a park pass and fishing license for Yellowstone online? If we have to do it in person then we would need to get down to Yellowstone before everything closes the night before. What is the earliest time we could start hiking in? I would love to hear from anyone who has done this before and any tips they may have.