In my own experience, people don't generally get stress fractures from one hike. When I hiked the Pacific Crest Trail it usually took about 100 to 300 miles of daily hiking for people to start getting stress fractures bad enough that they couldn't ignore them. My own stress fractures happened between mile 1000 and 1500 on the PCT and were caused by motion control shoes that I bought just before. I had to leave the trail and go home. At home what I did to heal was take slow walks totally barefoot around the neighborhood. It took about 6 weeks before there was no more pain.
I started researching to figure out what happened to me because at the time I didn't know what it was. I diagnosed myself as having metatarsal stress fractures. I read stuff about how barefoot is better than shoes and ever since then I have only worn flexible shoes. I've never gotten stress fractures again.
I agree with you that vibrams aren't that good for hiking, though. At least not hard-core hiking. Flat, smooth trails are okay, but long distances and lots of temperature variance and roots and rocks and stuff, they're just not as good as shoes or even sandals.
Female, 5'3", 49, Starting weight: 163lbs. Current weight: 135 (more or less).
Starting squat: 45lbs. Heaviest squat: 180 x 2. Heaviest Deadlift: 230 x 2