I recently got a new job in Denver, CO and I am planning a road trip out there from my current residence in Western, MA. The plan is to head out to Denver with my buddy and taking about two weeks to get there and then dropping off stuff and picking up my brother (who lives in Denver) and heading down to the Grand Canyon.

The rough draft itinerary looks like:

Day 1 - Drive to Niagara Falls
Day 2 - Spend a day in Niagara Falls and then drive to Cleveland
Day 3 - Spend the day in Cleveland
Day 4 - Drive to Milwaukee
Day 5 - Leave Milwaukee and head towards South Dakota - preferably staying somewhere halfway in between(central Iowa?)
Day 6 - Complete drive to Badlands
Day 7 - Explore Badlands
Day 8 - Explore Badlands
Day 9 - Drive to Grand Teton
Day 10 - Explore Grand Teton
Day 11 - Explore Grand Teton
Day 12 - Drive to Denver
Day 13 - Drive to Canyonlands
Day 14 - Explore Canyonlands
Day 15 - Drive to Grand Canyon
Day 16 - Explore Grand Canyon
Day 17 - Explore Grand Canyon
Day 18 - Drive to Vegas (stop at Hoover Dam on the way)
Day 19 - Vegas
Day 20 - Head back to Denver

We have the big ticket items on our list such as Mt. Rushmore, Old Faithful, Grand Canyon, etc. What I'm really looking for is advice on some off the beaten path activities or sights along that route, as well as must see sights at the national parks. I was also looking for advice on a place to stay and things to see between Milwaukee and the Badlands. I was also looking for advice on campgrounds around Niagara falls. I haven't been able to get a good feel about any of the sights there and we would prefer to stay on the Ontario side. Thanks in advance for your thoughts and contributions.