Each tour is a practice for the next. I had also done a fair amount of camping and backpacking before my first overnight cycle trip in 1982. I did quite a few of those weekend trips before my first week long trip in 1985 and multiples of those before my first cross-continent ride in 1992. They weren't necessarily planned to be preparatory trips as this is how it naturally happened. I still do short overnights now in between longer trips since I enjoy them, but they also check out gear before the next long trip.
As far as learnings go:
- early on I learned that bike maintenance and particularly functioning brakes are important
- I learned to develop a checklist to make sure nothing was forgotten
- I learned to take fewer clothes since it is extra weight
- I learned to wash in the sink with woolite
- I learned to check bolts to make sure they remained tight and didn't rattle off/loose, e.g on racks
- I learned that a stove is extra weight and there is a surprising amount of no-cook foods; so I rarely bring stove/pans on trips anymore
- I learned my own style and preferences of riding early, motels vs. camping, etc