Escorted Kyoto Taxi Tour

I have some friends in their 60s who have booked a 2 week escorted tour which includes Tokyo, Suwa, Takayama, Shirakawa-Go, Kamikochi and Matsumoto. They would like to arrive early and visit some other must-see places like Kyoto.

I think that an extra 5 days - a 3 day stay in Kyoto plus travel to and from Tokyo would probably be sufficient to round off their trip. However I am wanting some suggestions for bus or taxi tours since there is a lot to see in Kyoto and they may be limited in the amount of walking they can do.

Are the Kyoto City Visitors Hosts recommended?

Are there sightseeing buses?

Check here for sightseeing buses.
Depending on the season, the content may change.
https://willerexpress.com/st/3/en/pc/campaign/kyoto/?mid=1197
Among taxi companies in Kyoto, MK Taxi is particularly famous.
https://www.mktaxi-japan.com/sample-tours
If you want to keep it reasonable, I think you should use trains, subways, and buses. (The bus may be congested.)
Use Japan Guide, Lonely Planet, etc. to choose the place you want to visit.
https://www.japan-guide.com/e/e2158.html
https://www.lonelyplanet.com/japan/kansai/kyoto

If you need a guide when traveling on your own, you can also request a volunteer guide in advance.
There are several volunteer guide groups in Kyoto.
https://www.japan.travel/en/plan/list-of-volunteer-guides/
List of English-speaking tourist information centers in Kyoto
https://www.japan.travel/en/plan/list-of-volunteer-guides/

How about this guy?

http://www.kyototaxi.jp/eng.html

I have never used his service, but seems to be fine since he is a professional guide approved by the Japanese government.

Thank you both for these suggestions. I'll pass them on to my friends.