gugie 

Once you get to 3 days, the kit you bring is the same kit that will work for a week or two. This trip was warm, no rain in the forecast, so I carried 12 lbs including the handlebar and saddle bags. The max weight I've carried on other trips is about 15 lbs. The added weight is typically a rain jacket and pants, a pair of lightweight long pants that can double as tights for cold mornings, a light wool sweater and some wool t-shirts. I use a "3 days before needing laundry" rule, and look for a laundromat on the road. If you don't mind washing and drying your clothing every night, you can get by with less. My calculus is that an extra few pounds of clothing let's me spend more of my time doing fun things (drink beer and tell stories) rather than washing clothes.

Some tips:

Soaking wet socks from a rain storm we had to ride through on one trip were dried out in a hotel microwave. Try a short cycle, check, and increase until your clothes start to just about get steamy. Repeat till dry.

Bikes make great clothes hangers

I select clothing that dries quickly.

If you're going with a group, you can collaborate on tools. I always tell people to be self-supporting for flat repairs, but no need to bring several tubes in a group as they can be community property on a tour. One chain tool, however, will support the entire group, for example.

Half of our group had a GPS unit, more than enough to make sure nobody got lost or made a wrong turn. The route was done in Ridewithgps, so some went old school printed cue sheets.