Back in 2006 I did a 750 mile brevet going from Boulder to 100+ miles into Kansas and back. We picked up US36 a few miles east of Denver. Strasburg. US36 seems to start by I-70 a few miles east of Denver. We rode the shoulder of US36 all the way to the Kansas-Colorado border and then 100+ miles into Kansas. It was an OK road to ride. Not much traffic. Hills were big rolling ones. Lots of flat too. We were on US36 for about 300 miles in each direction. Once you get further east in Kansas you would likely want to get off US36 and onto smaller state roads. Traffic probably picks up the further east since the east is where all the people live in Kansas. And in Colorado no one lives in the eastern third so no traffic.