What lens should I bring on my White Mountain hikes?

[erno james]

Three suggestions:
1. If renting an L, the 24-105 f/4L is a great all purpose lens
2. If want to guy super light, buy instead of renting the 40 mm pancake. I consider it a must own for any canon shooter. Weighs nothing and takes up no space.
3. Take both above.

[neuroanatomist]

1. If renting an L, the 24-105 f/4L is a great all purpose lens

I'd agree...if the OP had a FF body. Personally, I'd not recommend a mountain hike without a wide angle lens (24mm x 1.6 = 38mm FFeq, and that's 'normal' not wide).