I have taken highway 78 from El Centro to Blyth and did not find it remarkable for any steep hills, or other reasons.
You will find less expensive gas in Arizona, and if you will be going all the way to Phoenix, then highway 85 north to Goodyear is another option that works well. Highway 95 to Quartzsite is also a great road.
Several times I have taken highway 8 further east to a cut off going north through Maricopa, via highways 84 and 347 when my destination was Gilbert AZ. SO I guess it all depends on your destination. When I wanted to see Slab City, I took highway 111 to Niland, and slab city is just east of there, an old Army base, popular with dry campers in the winter.
Have fun!
Fred.
Money can't buy happiness but somehow it's more comfortable to cry in a
Porsche or Country Coach!
If there's a WILL, I want to be in it!
I havn't been everywhere, but it's on my list.
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