Hello Yellowbelly,
My wife and I now have first hand experience driving up the mountains & hills of Colorado!!!
We left on Monday April 25th from Colorado and drove our 97 FD to Arizona and then back to Colorado the following week...
I can honestly tell you that going up those mountain grades was a little slow, but totally painless.
Here's the secret: Get to the far right lane, turn on your flashers, take your time & enjoy your surroundings, you'll be somewhere around 2500-3000 rpm's at 30 mph!!! There's also quite a few passing lanes which allows you to get further right thus allowing faster traffic to pass safely...
Once we got comfortable with the fact that going up hills or inclines wasn't going to be fast, the trip was just fine!!!
Happy travels,
Gary & Donna Allen...