GSPs definitely do have an off switch and many people on the GSP board I go to both camp/hike with their dogs.
If you were interested in a GSP, find a breeder that breeds a closer working calmer dog. One of mine could run all day non stop (that is no exaggeration -- she is heavily field trial bred) and the other is content to sleep in bed all day and then turn it up a notch when we go places.
I think you could find what you want within any breed as long as you commit to the necessary training to make it a great camping dog. But GSPs definitely do love the outdoors and the short coat is convenient after walking through thick prickly cover. Mine love the water, too.