US 34 reopened this past Memorial Day weekend (2018) after a 2 year rebuilding project that closed the road for the past 2 winters. This due to the flood of '13. There have been several new rock cuts to straighten out the roadway, and more 3 lane sections have been added for passing. The bulk of this construction has been in the area between the mouth of the Big Thompson Canyon and Drake. The Narrows near the beginning of the trip up from Loveland, is quite twisty, but everyone is going slow anyway so it's not a problem. There's still on-going construction but most of it is along the river and in areas that minimally impact traffic. But do watch for construction trucks turning on/off US 34.
US 36 was also rebuilt, prior to US 34, also due to the '13 flood. The Town of Lyons was particularly hard hit, along with the lower portions of the canyon NW of Lyons. Like US 34, there are new rock cuts on US 36 where the roadway has been raised up and away from the river. Once past Pinewood Springs, there was not as much significant damage from the flood. As others have pointed out, this is an easy drive up, there's minimal "twisties" and no drops offs to speak of.
CO 72/CO 7, the Peak to Peak Highway from Nederland to Estes Park is a wonderfully scenic route. But it is in the mountains, so there will be curves...lots of curves, and some ups and downs. If time permits, taking a breather at Brainard Lake is well worth stopping for a few hours. Brainard Lake road has recently reopened after a reconstruction project, where the lower 2.5 miles were completely rebuilt.
The worst part about the Peak to Peak is the approach coming in to Estes Park, which is a rather long 7-8 mile downhill, and there are some drop off areas there. And the road surface is seriously bad from the Boulder/Larimer line to the EP town limits.
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