well, because it has a max 180 mile per day limit with per-mile costs above that. So if you're staying overnight, that's one thing, but doing a 2 hour, go kayaking, 2 hours back type drive doesn't work.

Pointing out that it makes sense to calculate the actual dollar amount of the per-mile cost. I haven't done 2-hour round trips, but I've done 1.5-hour and was surprised how inconsequential the markup turned out to be.

This was several years ago and in Canada, so conclusions may differ.

2 hours each way for a day-trip?! I'm always shocked that people suggest that much driving as a proportion of the total trip time.

Eh, 2 hours, hike for 10 hours, 2 hours - you can do that all while it's still light quite easily in the summer time, and 10 hours of hiking is a damn good day :)