I know it is "Too Late" but campgrounds for the Big Rigs around Denver are few and far between. We stayed in a small one in the little town of Elizabeth recently its about 25 miles due E of Castle Rock. Pretty much bare bones but quiet & good elec/water...Jelleystone is a farce, way too much $$$ for what you get. I-25 is absoloutly bumper to bumper 24/7 and the trains are close. You will actually feel them. Heavy grade for them and pulling 100-120 cars of 130ton coal, those big diesels are working hard.
Jim & Chris could have maybe helped you out.