and I must admit as a Westerner there is no place better -
You have incredible options.
Is Denver a definite destination?
From Nebraska, US 138 to Sterling is nice but then it gets tricky.
Hwy 14 to Fort Collins has light traffic and Hwy 14 is a beautiful ride over Cameron Pass.
If you want to ride Trail Ridge Road in Rocky Mountain N.P., be aware that it is busy in summer.
Between you and me, I wouldn't head any further south than Boulder - nice college town -
Still, Fort Collins is a nice college town, too, with lots of bike services.
If you want to head into Denver - catch a shuttle from either location.
I love accessing RMNP via Cameron Pass - the Never Summer Mountains.
There is a service road that heads along a canal in the far NW corner of the park.
(Great cross-country skiing in the winter, too)
Then you can hike into the wilderness.
Walden is on the TransAm bike route.
If you are starving for company, then it make sense to follow the TransAm for a while.
But other routes are way more interesting. They do require a few miles of hard-pack roads, though.
One is via Steamboat, Craig, Maybell, Lodore, and Rock Springs.
Sections of US 40 up to Craig have moderate traffic - but then it gets really empty.
If you can arrange it, you can raft thru the Gates of Lodore in Dinosaur National Monument.
Spectacular canyons - kinda expensive though.
The ride up to Rock Springs is empty and lovely.
The other route is north from Walden to Encampment, Wyoming -
Then taking Hwy 70 over the Sierra Madre Mtns to Baggs.
Two miles south across the Colorado border is a paved road - Little Snake Rd
Mostly paved to Hwy 430 - 15 miles of hard-pack - true paradise of the empty West.
If you take either of the options you head north from Rock Springs on US 191 to Pinedale.
(Rock Springs has great railroad history of the Union Pacific - the first transcontinental RR)
If you leave Rock Spgs early in the morning, you will see the Wind River Mtns all day.
Pinedale has some spectacular scenery nearby - means heading out and back.
The best is Green River Lakes and Squaretop Mountain. Fabulous hiking.
As beautiful as the national parks with a fraction of the tourists.
Also - continuing towards Jackson - you should head to Granite Hot Springs
West of Bondurant - hot pool at the bottom of a waterfall!!
The advantages of riding via Rock Springs and Pinedale are many -
But you also can take full advantage of Jackson Hole and the Tetons.
There is a nice bike trail alongside the park road - it is a magical ride.
Plus there are hiker/biker campsites at Jenny Lake.
Plus-plus you can store your gear and hike into backcountry sites near Leigh Lake.
Yellowstone is not to be missed but requires caution in mid-summer.
I like to ride early and late - there are hiker/biker campsites at most campgrounds.
Morning and evening have far less traffic.
There is a fairly big climb from the south entrance to Lewis Lake.
I find an evening - i.e. after 6:00 - ride pleasant and shaded.
Lewis Lake has much quieter camping than Grant Village.
The TransAm route through Yellowstone cheats you out of the best.
Take a look at the park roads and notice the "Figure 8" pattern.
I would suggest Grant Village to Lake to Canyon to Norris to Mammoth.
That way you get to ride along Yellowstone Lake - take the Gull Point Rd -
And then ride through Hayden Valley with all of its wildlife.
Norris has a nice, small campground - the geyser basin is lovely in the evening.
From Norris, you can do an out & back to Old Faithful via Madison -
Then leave the park via the north entrance after visiting Mammoth Hot Springs.
Better quit now - - what to show you?? - - the Cathedral Group in Grand Teton - -