My wife and I have taken several bike trips in Europe, usually one week stints within longer stays. My thoughts:
1. There are real advantages to booking through a wholesaler. We've booked our last two longer trips through a British based wholesaler, Natural Adventures (which we've also used for hiking trips). You're still travelling independently, but the wholesaler books hotels, transfers luggage, arranges bikes, sometimes includes short bus or vehicle transfers/shortcuts (e.g., on a couple of long uphills in the Alps), and provides detailed maps and route guidance. Natural adventures was quite reasonably priced, but some of the better known tour operators (e.g., backroads) can be much more expensive.
2. Now that we're getting older (mid 60s and mid 70s), we've rented electric bikes for our last couple of trips (Passau to Vienna on the Danube bike path and Portugal to Spain across the Algarve). Not only does that save a lot of sweat and energy (particularly on unavoidable short steep uphills), but you arrive at your destination each night with enough energy to take sometimes very interesting sidetrips, many of which would difficult without an electric!
3. It is important to consider your route, the season, and the extent to which your route is bike friendly. Busier secondary roads can be crowded and scary (and often don't have dedicated bike lanes). We were much happier on tertiary country roads and even happier on dedicated bike routes! In this regard, the Danube bike path (about 95% bikes only) was wonderful. Similarly, we've followed wonderful dedicated bike paths along the Inn River (think Innsbruck to Salzberg). We were more often on roads in the Algarve, which was fine in April, but I'm not sure what it would have been like in high season. When we were hiking and car touring in the Dolomites late one spring ,we passed literally hundreds of bikes on the very busy (and often bike unfriendly) mountain roads.
4. Many hotels rent bikes (often electric) and there are other bike rental locations in most cities. So it's often fun to rent for 2 or 3 days for "spoke and wheel" trips with no need to book additional hotels or worry about luggage transfers. We've done this in the Innsbruck area and also in the Loire valley.
5. We are thinking about taking another bike trip late next spring from Innsbruk to Bolzano (likely through Natural Adventures) and would love to hear from anyone who's done it.
