I'm really interested in getting into fastpacking someday. The last few years I have competed in ultra distance trail races and would like to combine that with backpacking to do some longer routes like the Highline Trail in the Wind Rivers. I'm thinking of getting a lightweight pack and a bivy sack. Carry food I don't have to cook. So basically just have a light pack, bivy sack, cloths, food and a water bottle. Am I on the right track? Sleeping gear is what I am most concerned with. Want something really light but also don't want to totally freeze. Don't mind being a little cold though. Water treatment is another issue. Not sure what to carry for treating water.