I have not been on the Rubicon before but I understand the rough part is around ~12 miles long and takes ~5 hours for an experienced driver to complete and ~11+ for a novice. I typically hike at 2 mph on really rough stuff, 3 mph rocky trails, and 3.3 mph on groomed trails. So, a decent estimate would be 4-6 hours to hike the Rubicon - or faster than most drivers

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Just my perspective and why I don't have a Jeep/Bronco etc. Rockcrawling may be fun but it's a slower and more expensive than a pair of hiking boots. I use my rig to get me and my family to the trailhead or the backcountry campsite, not to replace the act of hiking.