This is from our trip across America when we moved out to California in 2017. It's about 11 miles off of I-70 but that is about 40 minutes each way. Smaller and less popular than Monument Rocks (though probably remnants of the same geologic formation) it was still pretty cool to visit. 
A couple of things to note. You will be on private property but I have been told they are okay with it (did see any no trespassing signs). The rocks are deep into the property and the road is no great. Our car is not four wheel drive but did have higher than average clearance. Still there was a point where I really thought we were going to get stuck just on the way out. I would say don't do the loop like us. Stick to going to the main rocks and going back the way you came in if you car doesn't have a high clearance and 4 wheel drive.
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