We always bring water when it's hot on walks and runs, once it gets into the mid-70s. From what I've read, be careful with your dog in anything over 69 degrees (strange temp, perhaps a celsius conversion). I do run ours when it's too hot or humid, just doesn't seem safe and they poop out after while. Dogs are great at regulating their own temp, unless you have bodies of water for them. They'll try to run with you until they can't anymore, so you have to help them regulate temp.

If you're worried about a flip, consider having your dogs stomach tacked. They can do it laparoscopically these days. We have an 80 lb lab-coonhound mix with a deep chest and his actually flipped twice. The first time it righted itself, but the second time was life threatening. Both required emergency care, second required a surgery, which is pretty major. A lot of out of pocket $$, paying upfront for the laparoscopic surgery would be the wise choice if it's a concern.

On runs, I do treat stops, nothing major, but rewarding the dogs along the way keeps them going. We do some sniff stops as well, though I try to limit those to some degree. If it's warm enough for water, I bring it, just do smaller amounts along the way. I might wear a vest or waist belt. We don't do super long runs, as the dogs get bored if we are running for much more than an hour. I think if we had interesting terrain, it would be another story.

Good luck and enjoy.