agesilaus wrote:
On popular trails in YNP you will be in a crowd. Like the trail to Yellowstone Falls. But there are hundreds of miles of less traveled trails and on some of those you will not see anyone. Popular trail after all implies lots of people want to see whatever it is. Just remember that YNP got over 4,000,000 visitors in 2015 and the Shenandoah probably gets less than a few percent of that.
YNP trails have their own special dangers that you should be aware of. First of course is the Grizzly bear population. Carry bear spray. And second is the geological hydrothermal features. There are a lot of fumaroles and such that you might encounter.
The hiking trails were not busy when we were there in mid-June. Yes, carry bear spray and enjoy your trip.