We are 4 adults extremely fit and looking to hire a private tour guide in each location. I lived in Germany for 4 years plus my wife is from Frankfurt area and I have been to these locations on business and but pleasure. Plus this was 20 years ago. Since we want to make the most of our limited time and prefer a private guide. If Rick Steves' has such options great if not recommendations much appreciated.
Thanks!
Rec getting the pocket guide from RS and then looking up who he lists. for example https://spainfred.com is who we used for Madrid for a tour of the Royal palace in Madrid.
Since your wife is from the Frankfurt area, consider reaching out to local businesses there. Perhaps a charming local cafe owner or a bike rental shop could recommend a fantastic guide with personal connections to the area.
Above post by youssefkhouiammi reported for self-promotion.