Chamois cream is a personal thing. This is an endurance ride. You'll be sitting on your saddle a lot. Take it, but you may be able to coordinate one large tube for the group to save weight. Is there any way the group can coordinate on other items like one bottle of Ibuprogren rather than one for each person? One good emergency kit for the group? One roll of duct tape? You could really all get loaded down without some coordination.

Never heard the maxi pad thing. If the huts are stocked with plenty of fresh water, wash that day's pair of shorts, turn them inside out and stick them in a mesh bag on the bag of your hydration pack. I know, I know. Like sticking your underwear out there in public but better than the other things that can happen. As you know, this is an incredibly dry environment so they'll dry fast.

I'd find out how much water the huts are stocked with so you could get away with a re-usable wash cloth rather than hauling baby wipes. Anything to save weight. If the water is limited, bring the baby wipes.

The snack stuff - I agree with FixedGearGirl. I've always brought my own snacks and electrolyte drink because I know what I can stomach on a long day and what will be tasty. However, on one trip they supplied Sour Gummy Worms. Wow, those worked real good! So we were happy to switch to their snacks.

Are they supplying pillows? You may want to take a case to fit those also. We use fully-supported mtbike touring companies but tent camp so we use the small pillows that you can get a REI, Campmor, etc. I made small cotton or flannel cases with draw strings for everyone in our group one year. The bags could do double duty as ditty bags or turned into a pillow with a fleece jacket and be personalized at the same time. Silly, but functional. I sleep so much better with a pillow.

Oh yeah, you know the cheapo shower caps you can get in hotel rooms? Collect those and see if they'll fit on your helmet. Tiny, lightweight and a rain cap for emergencies. They could go on your head underneath if necessary but I'm not sure if the water won't then be channeled down your forehead. Anyone else's opinion? Maybe the drugstore has larger sizes.

Anything that I have attached to my hydration pack goes into a mesh bag and gets a tiny carabiner so if it comes out from under the bungee cord, it is attached. I hate it when someone says "hey, where's my so-and-so?!" It won't be me riding back down the trail to find it.

Check the mileage per day. We had a couple of 50 mile days but we weren't hauling gear which will make you slower. Do some training based on the X hours you think it will take you per day at whatever pace you think you can maintain day in and day out. The riding in SLO is definitely in your favor. I'm in Davis at 52 ft above sea level and about 150 ft of climbing over 15 miles. Yeah, those are some hills we got here.

What company are you using? You hauling your gear via panniers, trailer, what? Since I've never hauled my own gear I'm always interested in what and why of this. I've got a BOB which one day will be used for the purpose but until then it hauls Farmer's Market goodies pretty well.

I'm getting so jealous. That area was our first mtbike tour and is probably my favorite just for the scenery, the air, the something.