A zipcar’s not really for the use case of a weekend away tho’. It would be a traditional rental like Hertz or Avis, then you have to pick it up the night before, load it, then when you get back late unload it, drop it off, then get back home by some other means...

Why not? I use ZipCar for long weekends frequently.

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 :)