I must agree with Valygrl. Google Maps can really get you into trouble.
Heck - it even dumps drivers off into the middle of nowhere at times.
If you do you Google maps - the operative phrase is - "Beware!"

Why? Because - -
(1) It is designed primarily for drivers - Point A to Point B.
(2) It will often put you on busy highways unsuited for cycling.
(3) Especially in the West - it may route you on private ranch roads.

There are two major factors that impact route suitability -
First, the volume of traffic - nearly all of us would prefer delightful country roads with hardly any traffic. Second, shoulders - if there is any traffic, it's nice to have the safety of a good shoulder.
Generally speaking, less than 500 vehicles per day is extremely low traffic, up to 1000 is low, up to 2000 is fair, 2000 to 4000 gets busy, more than 4000 is very busy. There probably will not be shoulders on roads with low traffic - less than 1000 - but you hardly need them anyway. In the mid range it is nice to have them. On busy roads they are essential.

So, how then do you find this stuff out? First stop - traffic volume maps from state departments of transportation. Google "State Name" and "DOT". Nearly all states have traffic volume maps on their DOT websites but they are in different places. Also many states have cycling maps - but they vary from good to pretty colors. Lastly, many states have county road maps on their state DOT websites - these are good to help find back roads - although not many states have traffic volume data for these back roads. (Generally, not always, you can assume light traffic.)

So here is a traffic volume map from Kansas -
(It doesn't hurt to have a state map/atlas out so you can cross reference.)
http://www.ksdot.org/burtransplan/ma...alFlowMaps.asp
Note that in west Kansas - Hwy 18, Hwy 96, and Hwy 4 have the least traffic.
(The ACA Transam route follows Hyw 96 and Hwy 4.)
US 24 and US 36 are fair, but busier.
US 50 and US 56 have the heaviest traffic and would be the worst choices.

Once you select low traffic routes, you will probably have some sections where you simply must choose roads that have heavier than ideal traffic volumes. Here is where Google come in handy. You can use Google streetview to verify if the busier highways have shoulders or not. By now, most of these highway sections should have streetview. If not, you can try calling the district offices for the state DOT - since they are the ones who will have the detailed knowledge of shouder conditions.

Hope this helps. - - J