Scenic Drives to/from New York
Since the first 'target' you listed was New York (presumably NYC) let's start there. There are certainly several scenic options, enough that you could take different routes out and back. So let's look at a couple of those. I'll describe both eastbound, but of course you could take either route either way.
1) 'Southern' route: This would take you through Kentucky and West Virginia, up the Great Valley of the Appalachians, and finally cutting through southeastern Pennsylvania and northern New Jersey to New York City. In Kentucky, look for routes numbered 90##. These are that state's parkways. Relaxed and scenic roads that are near-interstate quality. Specifically, the Western Kentucky, Audubon and Combs Mountain Parkways would probably be of most use to you. Mammoth Cave National Park is one possible stop. Your 'goal' on this leg is Beckley WV and getting set up to drive through the New River Gorge. From there it's up the Valley and Ridge Province of the Appalachians to Harrisburg PA and perhaps Gettysburg then I-76 into NYC.
2) 'Northern' route: This is, in my opinion, a classic example of there being scenery if you just take the time to look for/at it. Most people would simply get on the Interstates and be under highway hypnosis in just a few hours. But you can easily make it more interesting than that. Start with US-50 trough southern Illinois and Indiana, IN-101 past Mounds State Recreation Area and IN-44. OH-725, OH-503, and US-36 to take the scenic route around Cincinnati and then I-77 up to Canton. From there, US-62, US-621 and OH-225 would get you to I-76 and I-80 to I-79 north to US-6 across northern Pennsylvania, bypassing Scranton to the north. At Milford PA you be at the northern end of the Delaware Water Gap and depending on how far down-river you want to explore, either NJ-23 or NJ-15 will get to the New York metro area.
Now, both of the above routes are longer than the most direct all Interstate route, but they're also more scenic, have quite few attractions along them and avoid most of the large and even moderate sized urban areas. Also, while both routes could use a bit detail, the descriptions should give you a good idea of what such a drive would look like. I don't think you'd run into much hazardous weather along either of them in March.
AZBuck
Long road trip, need help...
Spring is almost here, Covid is fading, got my vaccines, itching to take a long solo trip. My starting date would be around April 15th. I want to plan a trip that goes from St. Louis to San Francisco to Las Vegas and back. I am looking at available time to be about 12 days on the road (not including 2 day layovers each in San Francisco, Las Vegas), a total 16 day trip. If I can squeeze a day or two in Utah national parks, it would be great.
I prefer scenic drives and natural scenic sites, not interested in historical sights.
Is it doable? Suggested routes?
Thank you for your feedback.
Doable, Yes. Worth it? Depends on??
Its certainly doable if it's more about the driving and short visits than anything else. How you divide your time will come with planning but you have about 8 days that will be dedicated to the drive, whether you want to add a few hours each day driving through places, or have a days break from driving every few days. You won't be able to get across the Sierra's by way of Yosemite so heading north via Lake Tahoe and south via Bakersfield to Vegas would work. 1-70 is a scenic Interstate and would take you near Glenwwod Springs, Colorado NM and Moab and Arches NP's and you could take US50 (aka 'The Lonliest highway') to Ely (past Great Basin NP) to Sacramento aan SF. On return from Vegas you the Grand canyon is a stand out attraction from where you could continue on I-40 and check out a couple of route 66 towns and Petrified forest, or take a scenic drive through Monument valley, Cortez, Durango, Pagosa Springs etc back to I-70. This would all be subject to researching road, weather and covid restrictions but at least it may be a place to start.
Personally speaking I would visit more of Utahs park (Capitol reef, Bryce canyon and Zion) and the amazing scenic Byways that link them and make my turn around point Las Vegas rather than going all the way to the coast. This will give so much more time to explore the amazing scenery and stop to smell the roses.