I personally don't agree that a first trip to Europe is easy. Like everything else in aviation, it's easy when you've done it once. The first time is a steep learning curve.
A friend and I took off to fly to Austria last May; I'd been to France once; she'd done something similar many years earlier. We learned a lot, had loads of fun, but it was quite stressful a lot of the time.
Charts - there are Jeppersons and the national ones. Both are available from most of the flying catalogues/shops, eg Transair. Pilot Warehouse is cheapest if you're getting a lot of stuff; I checked. Anyway, both types of maps have people who swear by them, so take a look and see which you prefer. Basically, I'd say if you're the sort of pilot who navigates with map and compass, uses VORs now and then, and switches on the GPS when you have to, use the national ones; they have far more detail. Otherwise the Jepps are fine. And I don't agree that you have to have a GPS; I rarely even switched mine on. However, if you don't have a VOR you would find it difficult in some featureless areas of France without GPS.
Get trip kits for every country you're going to, and study them before you go. And yes, the rules are different for each country. Unless you like learning lots of new stuff, I'd do one country at a time. We got thoroughly confused trying to remember what you could or couldn't do in France/Germany. It's not that complicated, but we didn't say that during the trip!
Look back at some old threads, and you won't get too caught out by long lunch hours in France, noise restrictions in Germany, and so on.
If you fly any high wing aircraft, I'd suggest an immersion suit instead of - or maybe as well as - a liferaft. Many people say that if you ditch, the aircraft will sink up to the wings, and you'll never get the liferaft out.
Don't get me wrong; it's not difficult, and it's great fun. But there IS a lot of new stuff on a first trip - and don't let anyone tell you otherwise.