Now we are sure. We will go to Las Vegas - because flights are way cheaper and more frequest from germany - and then rent a car one-way to go to Colorado and make a roundtrip there for 2,5 weeks. At the end we go back by car to Las Vegas.

Now we have to see how to do the trip. Durango seems a good starting point, as one-way-car-rental is possible to it. I will now see to take into account all the good ideas mentioned above like: Sand Dunes, Alligators, Loveland Pass, Rocky Mountain NP, ... and hope in the end we will succeed to see most of it ;-).

Help here is appreciated - expecially to find a trip which is not only upwards ;-)

yours Tobias