Joshua Tree National Park, about a three-hour drive from the city of Los Angeles, is home to Joshua Trees. If you have a day to spend, I would recommend a hike followed by the viewpoints.
Joshua Tree National Park at dusk
Lassen Volcanic Park has a lot to offer for everyone. The park has wide roads, and most tourist spots are easily accessible. Here’s what I would recommend
Lava Tubes Entrance
Sulpher bubbling in the background
There are three strenuous hikes. I would only recommend one or two of these
Taken along the Lassen Peak hike
At Lassen Peak
Cinder Cone seen from the bottom
Cinder cone from the top
Brokeoff Mountain Trail
17-miles 12-hours with a breath-taking dangerous climb holding chains on the majestic half dome at the end. This hike requires a permit for the final half dome climb.
Hiking Half Dome
12-miles 7-hours hike. The trail ends at a point higher than the Half dome. One gets a great view of the park as well as the Half dome from here.
Half Dome as seen from Clouds Rest
I would recommend doing only one of these two hikes in a single trip.
The lower falls are easily accessible with a short walk. The upper falls require a 6-mile hike. I only did the former.
Dry Yosemite Lower Falls during the off-season
Another gorgeous falls accessible with a short 10-minute walk.
Bridal Veil Falls
Glacier Point provides a great view of the half dome for non-hikers. It is located about an hour away from Yosemite Valley and close to south exit towards Fresno. For hikers, I would recommend doing Sentinel Dome or Taft point; both are one-mile hikes with starting point about 2-miles drive from the Glacier Point.
Sentinel Dome
Mariposa Grove has multiple hikes ranging from short walks to 7-mile hikes where one can see the giant sequoias. Due to time constraints, I only did the short hike here.
If you are doing in the Half Dome, then stay at the Yosemite Valley the previous night to start hiking early morning (4-5 AM). Curry Village has the cheapest lodging, and the camps are located conveniently inside the Yosemite valley. Book well in advance.
The park is huge. Roads wind around mountains and hilly. Driving inside the park can consume significant time, I would recommend planning for that in advance.
We did Zion Narrows on the first day. The hike consists of walking in the flowing water, which is ankle to knee-deep. Therefore, getting wetsuits and water shoes is highly recommended. The views are marvelous, and since one has to return along the same route, one can decide how far one wants to go. Total hike length is 9.4 miles, starting at the visitor center.