If you are doing marathons etc, hiking these distances shouldn't be an issue. But be realistic. Find a pace you can maintain---not one that wears you out. And just like running, you'll need a lot of fuel. My guess is that if you ease off the gas pedal a bit, and keep yourself hydrated and well fueled, you won't have any trouble. 17 miles a day is a long day---but at 2 miles an hour it's just over 8 hours. That's perfectly doable.