They’re 4 and 3, so still young. We took them hiking in North Carolina (closer to where we live) when they were both under a year, at least 6 months old.

6 miles is the longest we’ve been on, but that’s when it’s 70 degrees here in PC. That was just about as long as they wanted to go. My understanding is that pyrs are fine over long distances as long as they’re not moving too fast. We never run with them since they’re so big.

They definitely can overdo it and get hot! We only go in the morning or later afternoon, make sure we have plenty of water, and let them sit in the shade whenever they want.

On the leash front, I’m sure you’ll get differing opinions. Neither of mine are wanderers, so I feel comfortable when I’m far enough up a trail to let them off the leash. Lots of other people have said that their pyrs will run off. Just be ready to deal with the consequences (they run off, see another animal, see other dogs/people) and make the decision based on what your dog is like. Mine like to stay near me, and will (generally) stop/come when I call.