I've worried about my down bag getting wet for 40 years - never happened, so I'm working not worrying about it any more. A 32 deg down bag weighs almost nothing and has been great for me. I use potable aqua, drink a lot of tea, and skip the filter. I like the megamid - roomy, simple, and the places you describe all have enough shelter that wind has never been problem for me. Grand Canyon & S Utah - takes more creativity. Started carrying a 4 oz 3mil x 8 x 1 ft or so ground cloth ($11 Frost King Window insulation with grommet added to the corners) last year - got me through a rainy week on the Selway with no other shelter (barely). A folding bucket has been really useful for settling water if you suspect silty water. Fewer clothes than you think you need (always a puffy jacket, though). I use the turkey roaster for a fire pan and a 1 gal plastic screw top container for a groover (lasts a week or so, I usually carry food in an unused one so I have a spare). I get mine from a massage therapist friend (massage oil comes in them) & I think you can also find them at brewing supply stores. I've heard them called pickle jars.