Was Tolkien a Hiker?

[Mister Underhill]

Here's a little tidbit, from Letters:

The professional aunt is a fairly recent development, perhaps; but I was fortunate in having an early example: one of the first women to take a science degree. She is now ninety, but only a few years ago went botanizing in Switzerland. It was in her company (with a mixed party of about the same size as the company in The Hobbit) that I journeyed on foot with a heavy pack through much of Switzerland, and over many high passes. It was approaching the Aletsch that we were nearly destroyed by boulders loosened in the sun rolling down a snow-slope. An enormous rock in fact passed between me and the next in front. That and the 'thunder-battle' – a bad night in which we lost our way and slept in a cattle-shed – appear in The Hobbit.