I participated alone, even though I could barely speak English.
It was a half-day tour, and we were supposed to start at 9:00, but they were supposed to pick me up at my designated hotel between 8:30 and 8:45, but they picked me up exactly at 8:30. (I was the first one there, so I think we gathered at that time at the earliest.) After that, we went to pick up the other participants at their hotels and started. I was given a free bottle of water.
The guide was a cheerful man, and when I asked him questions, he explained things in simple English so that I could understand.
The waterfalls from the place he showed me were spectacular, and we went around about five waterfalls, and finally he brought me to a place like an observation deck overlooking the Columbia River.
On the way, we went down a road along a waterfall, and the next meeting point was at the end, but I didn't understand that, so I went back to the place where I was dropped off at the beginning. (The guide asked me if I understood the contents, but I answered YES, thinking that I understood.) When I returned, of course the car was gone and there were no other participants, so I didn't know what to do, so I called the number I had confirmed the reservation with, and someone other than the guide answered the phone. The person listened carefully to my poor English, and I was able to meet up with everyone safely. Although I had kept everyone waiting for quite some time, not a single person got angry. They all encouraged me with "Don't worry. No problem. It's ok!" and were very cheerful.
There were about 7-9 people in the group. The car didn't shake much, and it was a really fun memory.
Thank you for helping me even though I had gotten lost.