I too, have heard that the Virgin River Gorge is death on wheels for a cyclist. I remember reading an account of a tandem that tried to go through there ... and there was NO SHOULDER. That's right, miles of I-15 without any shoulder. It's apparently so tight through that gorge that even the feds couldn't build a shoulder through there.
I live in SoCal and can share some CA info ... before Interstate 15 was created, there was Highway 91 (the old highway between LA and LV). Portions of old Highway 91 still exist; and some are paved and some aren't. These portions, mostly paved, are found between a) Barstow and Baker, CA b) Jean, NV and Las Vegas c) Las Vegas and Littlefield, AZ (extreme NW Arizona). Littlefield is just west of the Virgin River Gorge -- that's the part where cyclists are directed to go north a bit over a pass and then east to St. George, UT so they can avoid I-15 through the gorge.
So, you can ride some of it if you really want to ... and Benchmark Maps' superb California and Nevada road atlases will show you exactly where these portions exist and where they are dirt or paved ...
... think twice about even attempting it.
1) If you haven't cycled in the SW desert before, it can be very intimidating. Almost scary. There's a lot of nothing out there, and though you're not far from help riding next to I-15, you have to accept a mental thing that what looks 5 miles away is really 10 miles away.
Also, the desert sun is different than the sun in IL or KS, for example. High elevation + low humidity = that sun feels like it's right on top of you. If you go to Las Vegas in the summer, it feels like the sun is being filtered through a magnifying glass onto the top of your head.
I do not cycle in the CA desert when it is over 80 degrees. That's about the point where you start to dry out. Along I-15 between LV and LA, there are gas stations and sometimes actual cities every 10-20 miles or so, but even so there are great distances sometimes between water sources.
And great climbs.
There are also some mountain passes. From LV (1,900') you climb to Mountain Pass just southwest of Primm, NV (4,000'). Then you come down off Halloran Summit (about 4,000') to the town of Baker (800' or so, one of the low points of the Mojave Desert). Then you would climb again, albeit more gradually over about 90 miles, to Barstow (2,100') and Victorville (2,700'), then immediately up over Cajon Summit (4,100') and down to San Bernardino (1,000') and the semi-arid, non-desert LA Basin.
In other words, there's a lot of long climbs. Some of them you will have to do on the shoulder of I-15 (the climb up to Mountain Pass from Primm, for example -- I don't remember a parallel road of any kind from my maps).
2) If you're seriously thinking about doing it, don't do it alone. And realize that it would be a major undertaking, in cycling conditions way different (and mentally and physically more trying) than in most of the Midwest and Plains states.
You dehydrate fast in the desert. Amazingly fast.
Now all that said ... it might be kind of cool to explore Old 91 between a) Barstow and the remarkably beautiful Afton Canyon, b) Bunkerville-Mesquite, NV and Littlefield, AZ, c) Las Vegas to Jean, NV. In fact, Green Valley Cyclists (check their website - Henderson, NV) has a route slip for routes down to Jean, which has a casino and hotel. But do it in fall or spring. Winter, you sometimes get a few inches of snow on the ground in the Mojave and the temps in January tend to be like 45/17.
Incidentally, there is a dirt powerline road, clearly visible on maps, which runs for something like 100 miles between Yermo, CA and Searchlight, NV ... but to my knowledge, no one has ever dared an MTB expedition on it.
Dirt roads in the Mojave are often sandy; some are gravel, but many aren't. And no one wants to bike in 4" of sand.
Last edited by firenbones; 06-03-08 at 12:29 PM.