It's clear that everyone tries to be kind and useful. However, I would caution that you narrow down and focus. Let's rank the spots as Grand Canyon, Yellow Stone, Yosemite as the top notch attractions. The 2nd tier has Death Valley, Grand Teton, Sequoia, Kings Canyon, etc.
My suggestion is Los Angeles-Las Vegas (en route to)- Grand Canyon, this may take 5-7 days. San Francisco-Yosemite-Lake Tahoe (en route to) Yellow Stone. This also takes about 7-10 days.
Please bear in mind that high places like Yosemite, Lake Tahoe, and Yellow Stone are still under heavy snow in May, though the roads are kept open. All the places become hot, except the City of San Francisco, in summer time. Travel agencies in LA and SF offer bus tours to those places, including hotels. But your freedom will be sacrificed.
My point is that 3 weeks should be enough, only if you don't over tax your schedule.
「Take only memories, leave nothing but footprints..」 Chief Seattle
媽媽咪,我們這圈用了一周,不算累。自己開車好玩,美國很方便的,安全。有GPS找路很容易。特別是想停就停,想照就照呀。提前把hotel預定好就行了。
Day1:SF to LV
Day 2: One day spent in LV (we visited LV many times).
Day 3: Left LV, went to Grand Canyon, passed Hoover Dam (On the way to Grand Canyon). Lived outside Grand Canyon in Best Western Hotel which is within 10 miles of Grand Canyon.(I feel quality is very good and price is cheaper than in hotels inside Grand Canyon).
Day 4: We joined a tour for Grand Canyon, but i don't think it is necessary. One day is enough for us. YOu can stay longer if you really like it. At the end of Day 4. we left Grand Canyon and went to Page, AZ.
Day 5: Had Water Rafting in Page.
Day 6: Left Page and drove north, passed by another national park - Zion.(on the highway to LV). Back in LV in the evening.
Day 7: Went to Death Valley and watched show in LV.
Day 8: Left LV
If you want to save time, you can consider flying to LV.
從地圖上看正好一圈。這圈玩得比較有效,緊湊但又不算趕路,景點都在路過。特別是Zion,高速經過,下來玩了幾個小時。
Post a failure example picture of Zion park here. 這種對比太強的景,怎末才能照得好點?
I've been to most of NPs around California, Arizona, Nevada and Utah. From my experience, Yosemite needs two days if you included the West Glacier and certain hiking (You should or you'll miss some pretty waterfalls). Sequoya an King's canyon one day if you were not going to hike. Grand canyon takes your two days if you want to touch both north and south rim (or one more day if you were going to taste the Colorado river water (very tough trip)). Don't forget Zion and Bryce NP. They are not far from Las Vegas. Both need one day. Not very far from those two NPs, there are Monument valley, Canyonland NP and Arch NP. The Arch needs one day. Monument valley half day is Okay. Canyonland needs at least one day (one and half day is better ) because it scatter widely. Death Valley needs one to one and half days. Grand Teton needs one day. Yellowstone needs two days.
These number of days are minimum and you have to get up early and hit the bed late.
You would feel really tired if you went all the places I mentioned, not just physically but mentally and emotionally.
Hope it will help you.
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