I was going to ask what size tires would be suitable for riding on gravel and wood chip trails- but it seems every different size is okay with some one here.

I'm planning a week long rails-to-trails ride in Canada next summer. My road bike has 700x28 and I think I need to buy a hybrid. I've only been riding the road bike for about 6 months, but 28s seem too skinny for anything but paved road - at least for me.