Another much longer way to avoid most of the I-15 superslab is to get on Nevada 93 just north of Las Vegas. North to Alamo, then to Caliente, over to Beryl Junction, UT. Then south on UT 18 to Enterprise and St. George. Or from Beryl Junction to east Cedar City, then up 14 (Cedar Canyon) to some very cool high country. These are all excellent motorbike roads is you have time and are interested in taking the route less travelled. See you up here on the V.
That's a great idea, I've seen that turn off when I went up that way to play golf. I've seen the whole route goofing around in that area in my Cherokee. Thanks for the reminder. I'll give you a shout when I get up that way.