My bad. It should have been 1697.
What I originally wrote was :
Let just say its more than a 1700 mile drive between Memphis and the bridge and leave it at that.
roadhound
So you are sticking to 1697. Hummmm. Mapquest for Californians must be different than for the rest of us

!Yah, Yah it’s more than 1700, and either 1679 or 1697 is along a route that has the same number as one of the roads crossing the bridge.
Any 1697 mile road Mapquest would route you on from Memphis runs east and west, so it is even numbered (eg I40). The only interstates that Mapquest can use to take you west to California, Nevada, and Utah are I40, I70, or I80. I don’t recall a US 70 in CA, NV, or UT, so the bridge is probably on US 40 or US 80. However it can’t be on US 80 because Mapquest would never route you along I 80 to any destination on US 80. So its US 40 across the bridge.
The bridge is over calm muddy water. Not in the mountains for sure!
The distance from Memphis to Barstow along I40 is 1679, not 1697, thus my request for reaffirmation (which you cleverly evaded

). It is important because you would leave I40 at Barstow for destinations anywhere in central or northern California (eg US 40 around the Bay area or Stockton, etc.)
So what do we “know.” At least one of the roads crossing the bridge is probably US 40. It is in California. If the 1697 wasn’t a red herring (which you now appear to be suddenly vague about

), then the route to the bridge goes along I40 as far as Barstow.
But piecing it together, the bridge is in northern California, in flat country, along US 40.
The next puzzle is what north south road no longer exists. US99 still exists. Maybe the Pacific Highway (pre US99) has lost its identity, but not in the hearts of us ole roadies......
Well, I have some “honey does” on the agenda this morning, but if someone hasn’t nailed it later today, I will very soon. I'm closing in (maybe!!).
I think I should get a free question!
Keep the Show on the Road!