The most important thing to do is demo as many different saddles as you can so that you know what works best for you and to really test it out. A saddle may be great for only ten miles or so but you might find out it is too painful for an all day ride. And spend the time and focus on the adjustments, slightly moving the saddle a few millimeters forward or backwards will make all the difference in the world. Selle Italia's Max line are incredible.

A suspension seat post is ah-mazing for trail riding.

Pearl Izumi X Alp Seeks are decent for short-ish distances - they're like a running shoe but with a cleat. Great for routes involving lots of walking but a bit flexy

I agree, these shoes are great if your route requires alot of hike-a-bike. They are flexy and comfortable enough where you can still wear them once you make it to camp. I used these on the Divide and was happy wearing them all the time. However, they do compromise on climbing though since they are so flexy.

I rode the Divide this last summer on a fully steel cross bike. There were only a few descents that were a bit rough but for the most part, it held up great. The further south I got, the more irritating the washboards were on the long fire roads, something to keep in mind.