5 days somewhere in Europe en route to London from Colorado

Looking for suggestions for a trip in the next couple of weeks for myself (late 40’s) and my 17 year old daughter for a last minute 5 day trip somewhere en route to London to visit family, leaving from Colorado. We have both traveled extensively in Europe. Together, most recently we have been to Turkey - Istanbul, Goçek, and Italy - Venice, Florence, Rome and separately my daughter did an EF tour of Eastern Europe visiting Hungary. Poland, etc. we usually love walking and exploring however I have just finished a year of chemotherapy and radiation and as such am more tired than usual and I think we would enjoy a beautiful city like Venice which my daughter and I both love, walkable, coastal, with good shopping or markets and cute restaurants. Or a small vibrant resort town close to a town that we could take a taxi to one day and walk around would be another option. Our budget is flexible. We like to go out to dinner. Thank you!