Route notes
Why this routing works
This three-week economy itinerary uses an open-jaw within Europe to avoid backtracking. It flies from Houston to Madrid, continues to Florence, then leaves the Europe leg open between Florence and Athens before the return from Greece to Houston.
With six nights scheduled in Madrid, the pacing gives the first stop the longest fixed stay before the intra-Europe flight to Florence. The surface sector into Athens replaces a short regional flight and turns the final long-haul homebound leg into a single return from the last stop rather than requiring a loop back through Italy.
For ticketing, the route works as a multi-stop transatlantic itinerary rather than a simple round-trip. That structure keeps the arrival in one European city and the departure from another on the same ticket, which suits a trip spread across Spain, Italy, and Greece in April.