Not to derail the thread, but is Ranger a flat coated retreiver? He's a beautiful dog!Check the local laws in your area, too. Up here, dogs can't be off-leash in national, and I think provincial, parks. So most of our hiking has to be on leash since those are the best trails outside the city.
Personally, I always keep Ranger on a leash regardless of where we are. Partially because he's a hunter by nature and because there's something about him that tends to "set off" wildlife. Knowing him, he'd go off tracking something and rustle up a bear...and then wouldn't back down
Not to mention his hunting endangers local wildlife. Even on leash he's caught partridges and pheasants and cornered a skunk
Back to topic: I wouldn't take Luke off leash because he does well until something very tempting (like a deer) comes along and then he wants to go make friends with it. He forgets I'm telling him to stay. I think he would try to approach a bear, alligator or whatever. He loves to chase bunnies, but always breaks chase if he gets too close. I don't think Luke actually wants to capture whatever he's chasing. :