Roads to avoid

William Willard wrote:
No Interstate Highway grade is over 6% -- That does not apply on other highways -- William Willard

The western approaches to both Vail Pass and the Eisenhower Tunnel on I-70 are both 7% grades for several miles.

East of the Rockies, we have found I-70 to be an easier drive than I-80. Fewers semis and generally better road conditions (maybe because there are fewer semis :h )

You are pretty much exposed to a fair amount of climbing no matter which route you choose, as all east-west interstates traverse the Rockies. I consider everything east of the Rockies to be kind of a null, a big empty nothingness to be driven across as quickly as possible. So considering what happens as you go south to north:
1-90. Goes into some pretty country in western Montana and stays there all the way to Spokane. Grades pretty easy to handle. Fourth of July Pass east of Coeur D'Alene a trifle challenging, but not bad.
I-80. Probably the most direct route but Jesus, booooring and almost anti-scenic. 400+ miles of Wyoming desolation, a little bit of scenery through the Wasatch to Salt Lake, and then 600+ miles of Absolute. Nothing. to Reno. Then, Donner Summit (beautiful, but can be challenging in weather).
I-70. The prettiest route; also the most challenging as far as traversing the mountains goes. You'll have the choice of heading north via US 6 to I-80 or south through Vegas to hit I-40 after you emerge from the mountains.
I-40. Mostly booooring but scenery through New Mexico and eastern half of AZ can be interesting. A good choice if weather threatens. Pass crossings are gradual.
1-10. A whole lotta nothing. You drag yourself across Texas, then 4+ hours of desolation to Tucson, and 6 more hours of absolute nothingness (yes, that includes Yuma; Yuma is nothing) until San Diego. Gasp gasp.

My choice would probably be I-70 to US 6 to I-15N to I-80 west. It's one of the two quickest routes, and the Rockies crossing is a lot more interesting than on I-80.

Avoid all of Indiana! Although there has been some work done on the Interstates (and I-70 is greatly improved), they are still (all of them) too bumpy and those expansion joints at bridges are still horrible. About the time a section of Interstate gets all fixed, repaved, or widened, within 24 hours "they" are digging it back up again and then patching with massive bumps and stuff. So, any repairs on I-70 done in the last 3 months will be trashed by Spring!

Avoid Indiana, there just simply ain't any good Interstates. If you do come through Indiana, take US highways. They are MUCH MUCH smoother than the Interstates.

loggenrock wrote:
You asked about roads to avoid... Here's one - Interstate 78 from NJ into PA. Not because of grades, but just poor road condition. LOTS of potholes/broken surface. ... ST

;) If potholes are the criteria to avoid a road: I-80 over Donner Pass, All Los Angeles freeways, I-5, CA 99, and I-580 into the SF Bay area. I am not sure if I-40 around Little Rock, and W. Memphis has been fixed up or not but it use to be a shocks shaker in the slow lane.

the real problem with a gas MH going over the rockies is towing a 3K toad behind. I know cousins of mine who have disconnected the toad and DW driving the toad over the rockies then hooking back up and continuing

You asked about roads to avoid... Here's one - Interstate 78 from NJ into PA. Not because of grades, but just poor road condition. LOTS of potholes/broken surface. At times had to slow to almost 40 mph so didn't shake things loose! Figure coming from MD this might be a potential on your list... ST

Take a look at https://www.flattestroute.com/

If grades are your only consideration, then I70 is probably the toughest but certainly doable with your setup.Have been across a few times with 32 ft gasser towing 3000 lbs.Will it slow you down? Absolutely so get in the slow lane and enjoy.
For my money the scenery along I70 far surpasses any other Interstate route, especially in western Utahnjoy your trip no matter which you choose..

Sandy & Shirley wrote:
As stated in another post, we are planning a 6 week trip from Baltimore to Oakland and back, southern route over and northern back. Thanks to all of the information so far, we are placing a lot of “dots” on the map for places to stop for a day or so and will soon start to connect as many dots as possible.

We will be driving a 37 foot Class A, gas not diesel, and we will be pulling a Ford Focus, about 3,000 lbs. Are there any routes through the mountains that we should avoid? Do all of the Interstates lower grades, or are some far more difficult to travel.

Again, thanks in advance for all the helpful answers that you can post for us.

Presumably, your southern route would be either I-40/I-20/I-10 selection, and northern would be I-80 or I-90. That leaves I-70 as the NOT selected route, for either direction. Probably a good choice, at least for Colordao.

Though the maximum grade is 6% at the Eisenhower-Johnson Tunnels, as well as most of the other passes you would encounter, there would be a lot of Up/Down to traverse, either direction. For some folks it's no big deal. For others, who have no or little mountain driving experience, it can be intimidating. Avoidance resolves that!

On I-80, your highest elevation will be ~9600 feet, and that's between Laramie and Cheyenne WY. There's a significant hill outside of Laramie, climb going EB, decline going WB, with the high point being at the summit east of Laramie. Not really a pass, just a high point on the high plains. Heading WB it's more gradual than EB to the summit.

Google Earth Pro has a route profile feature that will give you the highest point and the grades along a route.

Simply set a start and end point in Earth and right click on the route. Select Profile. Looks like this.