Found: 90s Childrens Fantasy Series

This was a series for approx elementary/middle schoolers about a boy whose name started with R, and the books had a titling convention of being like "R--- and the wanderers" or "R-- and the lost people" (not actual titles). The main character was a very timid boy with a very adventurous sister, and the first book in the series was about how their river ran dry which meant their fantasy beasts of burden were dying (they could only drink the "sweet water" of the mountains and the well water would make them sick). A group of people climbed the mountain to try to find out what was the wrong, and the timid boy was prophesized by the wise woman to be necessary so he had to go too. Eventually all the other big strong men/women ended up failing or being unable to go on, and the boy really did save the day. I believe they were also looking for a lost city that ended up being the ruins they walked through unknowingly.

The series went on with a bunch of other adventures, one I'm recalling had their town taken over by an invasive plant species that put everyone to sleep and another revealed that the villagers were related to a bunch of other captured slaves they saved I think.

help!!!

>1 rainbowrites: Rowan of Rin

omg thank you!!!

The one with the plants is Rowan and the Travellers.

>3 rainbowrites: You're welcome!