posted 08-15-2014 02:32 AM
I visited Peenemunde with a few friends in 2009 but we had two advantages: we flew there ourselves and we speak German. The island of Usedom is a regular German holiday destination, in fact there are a few scheduled flights to Heringsdorf in the east of the island. However, I think that renting a car and driving there might be more practical overall.
We flew into the airfield of the village of Peenemunde itself, which had been in use in WW2 and during the GDR era as a military base and thus is a minor attraction in itself.
The museum is located in the former Power plant, so not only the collection but also the building itself is very impressive.
There are a few more remnants scattered through the village such as the factory to turn potatoes into rocket fuel — however we didn't dare enter these abandoned sites.
The actual launch site and much else of the research facility is off limits unless you have a guide, at least that was the case in 2009. We did find a guide, but he only spoke German. To visit the site is very impressive but, to be honest, more for what it was than what it is.
As far as remains go, you have to think slabs of concrete, parts of railway tracks, etc., so in that sense you also need a guide just to make sense of it. Most impressive to me was the oval earthen wall around the launch site. Once you have seen that in real life you will frequently recognize it in documentaries.
Our guide also ran the Bettenmuseum, that is the Bed's museum. For legal reasons he couldn't call it the rocket museum that it really is. It had an impressive array of artifacts and was located at the entrance of the Peenemunde airfield.
I just looked up their website and it seems that the museum has been relocated to Karlshagen, a bit further east on the island. If you look at the website you'd have no idea that it is anything other than a Bed's Museum. 
In short, to us it was very much worth the trip. I do recommend trying to arrange a visit to the actual launch site however I don't know any other venue than to try the Bettenmuseum.