The biggest run of my life — both mentally and physically — takes place next Thursday. It is not just any run, but a trail ultramarathon in the Grand Canyon — from South Rim down to base, to top of North Rim, down to base and back again to South Rim. If all goes well — and there are a lot of IFS, ANDS, and BUTS — the run will be 43 miles long. It is not on flat surface or on streets, but on trails. So I have had to learn (and buy) a lot of gear for this new adventure. Though trial and error, and recommendations from people I trust, here is what I have that I love.