Dear SCG -
You do say this will be your first trip - but you don't say when you propose to do it. That is important because you are looking at riding
through the Rocky Mountains - which tend to be significant colder than surrounding areas and the Mojave Desert - which tends to be significantly hotter. And if you are going east-to-west, it is more difficult to find a workable window.
If this is your first tour, you might want to consider including significant segments of ACA's TransAm and Western Express routes.
Say, from Alexander, KS to Pueblo, CO -
https://www.adventurecycling.org/routes-and-maps/adventure-cycling-route-network/transamerica-trail/Then from Pueblo, CO to Cedar City, UT -
https://www.adventurecycling.org/routes-and-maps/adventure-cycling-route-network/western-express/I agree about avoiding riding thru big cities - it's tough and adds to the risk factors.
If you are meeting friends - you should have THEM come meet you - say in Pueblo or Cedar City.
Or have them come pick you up in these locations. Or you can leave your bike at a bike shop and take a bus.
(There is frequent bus service Pueblo-Denver and Cedar City-Las Vegas.)
Not sure where in K.C. you plan to start - but there are a number of eastern Kansas options.
One is to ride to Ottawa and then get on the Prairie Spirit Trail to Iola and connect with the TransAM kust to the west.
Another option is to use the Kansas DOT bike map and head directly west towards Alexander.
http://www.ksdot.org/Assets/wwwksdotorg/bureaus/burRail/bike/Documents/BicycleMapState.pdfFinally, on the western segment, I would suggest heading through central Nevada and then south in Calif on US 395.
That would entail heading due west out of Cedar City to Rachel and Tonopah to Bishop. Services scarce.
There are few to no back road options directly from Vegas to Victorville - forcing you to use I-15.
One possibility is to head south on US 95 to Old Rute 66 - extremely hot and extremely remote.
The other is to continue south on US 95 to Hwy 62 thru 29 Palms - still pretty darn hot and remote.
J