We purchased Rail Europe Multi-Day Scandinavia pass (waste of money for us!). I checked with the DSB train office in person at the Copenhagen station about plans to ride the train from Copenhagen to Svendborg to then go on to visit Aero. Was told our "rail pass" was a ticket but we would need a reservation and that was extra fee. I don't know it was confusing to us.. Train from Copenhagen to Odense needed reservation, train from Odense to Svendborg did not.
You must book the ferry in advance if taking it to Aero. We could not get a room on Aero so stayed at the Hotel Aero in Svendborg and took ferry over for the day. Unless you can't get a room on Aero I don't see any reason to visit Svendborg. Hotel Aero is rooms above their restaurant and then additional rooms across the street above another restaurant. The halls and rooms smell very musty, shower is just a drain on the floor in the bathroom with a curtain which makes for a slippery and wet bathroom. Even though the town was like a ghost town quite early in the evening there was a lot of noise when we tried to sleep with windows open (it was hot!). Breakfast buffet was good however.
Rick heavily promotes Aero. After visiting we honestly don't understand why. We planned to bike while here and rented bikes from Aerohus a hotel up the street from the ferry. You will need to go inside and speak with someone, tell them the number of the bike(s) you want and pay. Their bikes will have an Aerohus sticker and number, and they will be mixed in with other bikes not for rent that others have! We also checked out Pilebaekkens Bike Rental which appeared that you needed to reserve in advance, drop in like we did and we were offered just a small handful of bikes to choose from. Regardless of where you rent we found all the bikes to be really old, not well maintained.
We decided to follow Rick's bike tour outlined in the Coppenhagen & Best of Denmark book. Rick save the bike stuff to someone else. The biking tour he details is not clear, totally confusing and is just plain not correct and really needs to be wroked on if he's going to continue to include it.. This is the only time he's steered us wrong. Save yourself lots of frustration and see if there is a bike map available if you are determined to bike. The rental places did not have one. Aero unlike the rest of Denmark that we experienced is surprisingly NOT bike friendly in our opinion (and we are a family that bikes!).. There were no true, safe bike lanes so you are sharing the road with cars. The cars on Aero were going double the speed limit (they had radar posted so we saw!) . There was no shoulder on the roads either and lots and lots of hills. It was a hot day and we spent 6 hours on bikes getting lost, scary speeding cars flying by us and barely made our ferry back. If you want to bike in Denmark we wouldn't suggest doing it here.
Outside of the bike experience we didn't see that there was much of anything to do/see here, kind of a disappointing stop for us.
Next day we took the local train to Odense and picked up a rental car at Avis. We walked to the car rental office but had trouble finding it. This is because we needed to enter a garage bay and then there was a check-in office for Avis. It wasn't signed well.
We visited the new H.C.Andersen museum in Odense - Rick's book needs to be updated with the new museum info. You will need to reserve a time in advance! We did not so bought on arrival and had an hour wait till our entry time. To pass the time we visted his birthplace (small,cute house takes a few mintues to walk through) and walked around the city. The museum is cool and very Danish in design. And the design allows for a good flow so you are always moving and it never feels crowded. You will be provided headphones that narrate the displays you see. There were several "listening" stations that didn't work for us. Really worth a visit!.