That's a big dam' 5er, but thousands of other drivers do the same thing every week, so unless you hit a storm that strands EVERYBODY, you should be fine. The uphills around Eisenhower Tunnel and Vail have at least three lanes, so just stay right, let the cars and cycles pass you, and enjoy the drive. We did it in a 34' 1988 Bounder last year, so if we can do it, anyone can.
And enjoy Glenwood Canyon - but don't blink or you'll miss it - it's only what, about 15 or 16 miles worth?
Always remember, you're a unique individual. Just like the other 7 billion people on the planet...