Why would you have a 112 mi. round trip getting to Fishing Bridge? Go in from one direction and exit another. Cell service is available near Fishing Bridge - we've used it. Stock up on supplies before entering the park. They can easily last 1-2 weeks except for milk or bread. Take a side trip outside the park to West Yellowstone for a day of siteseeing that area and fueling up before going back to Fishing Bridge. Also, fuel in West Yellowstone is much higher than in Jackson. Do the West Yellowstone folks drive down to Jackson for fuel?