Do not like heights... Wow, that's not even a contest.
I-70 was such a difficult and perilous road to build that it wasn't even finished until the 1990s. It goes right through the center of the Rocky mountains. Through Glenwood Canyon, I-70 was built on a ledge and does all sorts of crazy cantilevering out over the river. (You can see it from Amtrak's California Zephyr). I swear they're using anti-gravity repulsors to hold it up. So negative Ghost rider. Wave off, wave off!
I-40 is deadly dull. You remember the movie Cars, where the freeway bypassed all the towns along the 2-lane road, and Lightning gets off the very boring freeway and winds up in one of those towns. They were specifically referring to I-40.
That's not really an insult. The freeways were designed to be deadly dull, because it reduces accidents. Although they prefer to call it "designed to a consistent engineering standard with modest grades, modest curves, and good sight lines (as far as seeing the road and other traffic), particularly on vertical curves (e.g. going over the top of a crest)". Even I-70 has this. It's just that with I-70, to put the road where it needed to be to meet those standards, it is often suspended seemingly magically in the air.
(Although, one part of "dull" that's "deadly" is drowsy driving. Utah is really big into warning people about that, but then, Utah has a freeway across the salt flats.)
This alone is the deal-killer for I-70. It's a wonder of the world, but not for you. https://www.youtube.com/watch?v=LNqcNH7ez4k
I need safe accommodation and rest areas on the road.
"Rest areas" as you know them in the east, with the full service parking, restrooms, vending machines, picnic areas etc. can get pretty sparse in the American west. Some states put minimal "rest areas" at an exit, out on the regular roads, so they can use the same rest area for both directions. I'm not a fan; it's too easy for people on foot to reach those and do crime.
All rest areas will be full of trucks all night. They are sleeping. The area will be full of the growl of diesel engines. These are the engines on refrigerated trailers to run the freezers inside them, or the trucker is running his diesel to run his cab A/C. That trick won't work for you. Do not attempt to run your gas engine while you sleep, or you'll wake up out of fuel or with a broken down engine!
Other than a decent full-service rest area, my top choice is any of the popular "Travel Centers" - Pilot, Flying J, TA, Petro, etc. They are perfectly fine and safe when they're in the middle of nowhere. One side is for trucks, one side is for cars. Choose the "car" side obviously. These are open 24 hours and it is safe to sleep in their parking lots. They're not quiet, but neither will be a rest area.
Those "Travel Centers" typically have a "7-11" type food store, a sit-down restaurant, and at least one fast-food offering better than "Subway" - McDonalds, Arby's, Taco Bell, etc.
I need to refill gas very frequently.
You'll find a travel center, or a town with a row of gas stations, at least every 100 miles (160 km). That will be more than often enough for any car. Use your smart phone, put the map area on the area 200 miles ahead of you, and type "Gas". It will show you where gas stations are in that area.
Your car will generally get much better fuel economy going 55 mph (90 km/h) on the freeway than it will driving around town. However, as your speed increases, your fuel economy will worsen again, until by 80 mph (130 km/h) it's "worse" by city mileage.
You don't have to drive 80 mph just because the speed limit sign says that. Many trucks are governor limited to 65 mph (105 km/h) and some even go 55-60. It saves fuel. Go the speed you are comfortable with. Know your "personal minimums" and be OK with that.
If fuel expense is a concern and you want to improve your fuel economy, here are my top strategies in order:
- Slow Down. The faster you go, the worse your MPG due to aerodynamic drag.
- Turn A/C off, put vent on maximum and recirculation on "outside fresh air". Keep the windows closed (they add so much aerodynamic drag that they're worse than the A/C!) If it's hot, it'll be HOT. Hydrate like crazy - always have two 32-ounce (1 litre) drink cups in rotation, one with a drink, one with spare ice. Almost every travel center will let you fill your drink cups with ice for free if you ask nicely. You'll want to stop every 90 minutes to re-fill ice and to pee - if you're not peeing you're dehydrating!
- If there's no crosswind, follow trucks. Lurk about 100' (7 carlengths, 2 truck lengths, 30m) behind. This causes a "drafting" effect if there's no crosswind. (yes, this works at 100'. I've played with this extensively with a car with instant MPG reading. NEVER tailgate!)
These combine nicely. If you're uncomfortable going faster than 65 mph, find a truck going 65 mph and follow it.
Cellphone signal is very important.
Check your cell coverage map. Generally AT&T and Verizon make an effort to cover every freeway and much of rural America.
Many cell phone providers (e.g. metroPCS) only market to urban customers, and only bother to maintain a cell network in cities. When one of their customers goes out into the country, either it doesn't work, or they rely on a process called called roaming - that is, borrowing the network of typically AT&T or Verizon, and that means your cell carrier is paying them for your usage. As such, the carrier rations and limits the roaming permitted. For instance they may allow voice/TXT roaming but not data roaming, or may squeeze data roaming speeds down to "check email" speeds. So have the "roaming" conversation with your cell provider if it isn't AT&T or Verizon.
Also keep in mind that they just don't have 5G (or even 4G) out in the sticks. It's not a deployment priority since there are so few users and the airspace isn't crowded (the main problem 4G/5G aim to solve).
Note it is both illegal and dangerous to be using a smart-phone or tablet while driving. When you are cruising at 80 mph, loss of control due to lapse of attention is much more serious! Further, the truckers have CB radios, and will get on channel 19 or 9 and tell the cops about any distracted drivers.
NTSB's position on any electronics in the driver's seat is that nothing should be used except for things designed to support the driving task. So, basically, maps.