Yeah, you used to be able, with a goodish rig, to get from the front range to Winter park via the Boulder Wagon road. It was steep and crossed over a big gas pipe a couple of times, and skirted a wilderness, which as I recall is why it closed... the gas pipeline was being driven over(how safe is that???), and the wilderness, those are issues. I also think it closed due to BS. as it was open for 100 years before the closure with no issues, until that darn wilderness moved in next door to it.
Bad neighbors ruined the whole neighborhood!