For information on Schiphol airport, you can go to
http://www.schiphol.nl/ and click the English button. If you click on the map, and check the terminal map, they have a great shockwave map showing you the train stop underneath the station.
If you happen to meet deafies, you can prepare yourself learning a bit NGT (Dutch SL) through this webpage:
http://www.effathaguyot.nl/index.php?stab=1 (in Dutch only...)
I wish you luck in finding a cheap airplane ticket. In September, it might be after the high season of summer travel, so you might get lucky and find a cheap fare. The best way to get cheapest is to travel on Tuesday to Thursday only. Like, fly there Thursday night, and arrive back Tuesday. Red-eye flights are also cheaper, and you can sleep on the way, arriving early morning in Europe.
Yes I have driven in Germany. The prices for petrol are very high, as they sell by litres. It can be like 1 euro per litre, and if you fill up like 40 litres, you can easily blow 40 euros away (about 50$) on one tank of petrol. You need to think about that. How far are you driving, how long, etc... Granted, with cars, you have much more flexiblity and freedom, but there is a price to pay for that. With trains, it can be done but you would have to follow a programme.
As for parking, I really didn't have problems parking my car. If you see jagged lines ( |\/\/\/\/\/\/| ) on the side of road, that means parking is prohibited there. Also, if you see a red sign with a X over blue field, that also means parking is prohibitied there. For more road information, go to this website:
http://home.att.net/~texhwyman/autobahn.htm and
http://home.att.net/~texhwyman/zeichen.htm
Indeed, Autobahn doesn't have a speed limit. The best rule is to keep to the right as possible, and pass only when you have to pass. Don't stay on the passing lane just for the hell of it. A lot of ppl will be driving about 200 (125) to 250 kph (155 mph) and will flash their headlights very far behind you. You might think that they are just getting on your nerves, but the warning is real. They cruise at 250 kph, so they will arrive very fast behind you. Also, NEVER pass on the right side of a car. You will be ticketed automatically if a police catches you doing that.
Absolutely, I plan to go back to the Netherlands one day and visit more of the country. Same goes for Belgium. I have been to Europe 5 times, and my first time was as an exchange student in Germany. If you have any additional questions, feel free to ask me.