I'm in the same boat so to speak although my desire to travel afar is no longer with me. Here are a few sites that may be what you are looking for...

--- Educational Slower Paced Tours For Seniors - Browse our collection of slow-paced tours for seniors with limited mobility or little walking included: https://www.roadscholar.org/collections/at-a-slower-pace/
--- 10 Vacation Ideas For Seniors With Limited Mobility - YouTube: https://www.youtube.com/watch