Fyrestorm said:
Yes, we are hikers. After Yosemite our plan is to hit Yellowstone/Tetons for 7 days and then Glacier NP for 8 days. Hiking will be our focus in Glacier. We've done some trails in Yellowstone and the Tetons We are good for 8-10 mile day hikes. I hear the 4 mile trail in Yosemite is good. What do you suggest?
I have spent a lot of time and done a lot of hiking in all four parks you mention. Here are some of my humble opinions:
Yosemite:
4 Mile is a great hike. In fact it is my favorite Yosemite hike by a narrow margin. What pushes it over the top for me is that once you get to Glacier Point there is an ice cream store waiting for you! However, they LIE. If you check out the photo below you will see I am not yet at the top and the sign says "4.6 miles to the valley". Since it is a quarter mile from the parking lot to the trail head 4 Mile Trail is actually 5 miles long, one way, 10 round trip. Of course the 5 miles downhill is a piece of cake and you can practically run all the way down it. So why is 4 Mile Trail 5 miles? The trail was carved in the 1870s when a businessman opened a hotel on Glacier Point. He had some kids that needed to go to school on the valley floor. So he built the trail so his kids could go to school. Now as you hike this trail think about those kids hiking this trail 5 days a week just to go to school. When the trail got opened to the public it was too steep, so they redesigned the trail and made it flatter, which made it longer.
Nevada Falls and Vernal Falls Trail otherwise known as the Mist Trail. Almost as good as 4 Mile, but without the ice cream. This trail has several different routes that are optional. Make sure you make it to the top of Vernal Falls. It is a 7 mile hike and be sure to leave early. It is the most popular hike in Yosemite and the trail becomes a freeway by noon time.
Upper Yosemite Falls is a great hike but I don't recommend it in the summer. 4 Mile is great because it is on the south wall of the valley and you are in shade most of the hike. Lower and Upper Yosemite Falls Trail is on the north wall and there isn't much shade. You will roast in the summer time. But at least take the half mile trail to the Lower Falls.
Mirror Lake is an easy 2.5 mile hike on the valley floor with spectacular views of Half Dome that you don't get any where else. Mirror Lake could be the most beautiful lake in the country if it wasn't for Tahoe. Once again, go early, it becomes a freeway.
I have never hiked Half Dome and I probably never will. It is a truly spectacular hike up the backside of Half Dome. You are going hand over hand on chains and it is 14 miles.
http://www.yosemitehikes.com/yosemite-valley/yosemite-valley-hikes.htm
Glacier:
The Hidden Lake hike is another one that should be on your bucket list. It is an easy trail and it is about 3 miles round trip. The two photos I posted were taken on that hike in AUGUST. Notice the snow. Lots of wildlife on this trail. A flock of Bighorn Sheep live up there along with wild goats and marmots.
Highline is absolutely amazing also. It is a very long hike but pretty much all downhill. There is a spot that requires going hand over hand on a "highline" with a drop off that is not for the feint of heart. It is also possible to go to Logan Pass and hike a mile or two down the trail and then return to Logan Pass.
Avalanche Lake is a 5 mile round trip that becomes a freeway. The payoff at the end is world class. Avalanche Lake must be seen to be believed.
The Tetons:
Since you have hiked the Tetons you are probably already aware of the Swan Lake Hike. When I stay at The Tetons I hike it just about every morning. So much beauty and wildlife on that hike. There is an active Osprey nest that can be seen from the trail. Every morning at 8 am there is a ranger led hike on the trail and I go with them about every other day.
The hike around Jenny Lake is about 8 miles without the option of going to Inspiration Point. Or take the boat across the lake and hike to Inspiration Point. Either way is spectacular.
Yellowstone:
Artist Paint Pots Trail is an easy hike on a boardwalk, but not to be missed.
There is a hike that goes to a waterfall behind Grand Prismatic Springs and I can't find the name of it online. Another knockout.