Can you go over 200 miles between gas stops? If so, a good stop will be Exit 18, Woods Chapel Road, then go south 1/4 mile and there is a QT, good place for gas and coffee. About 10 minutes from me and 2 mins from Tom's work.
As far as traffic there will be a lot of semi traffic from Columbia Missouri to KC at that time because they will be leaving the truck stops and heading into KC. Rush hour on I-70 starts to get thick at about 6:30am and the worse part isn't necessarily downtown. Through Independence and into KC is where is gets bad. I drive that way a few times a week and it can be smooth sailing to downtown (15-20min) or it could take a solid hour. I am thinking the best bet would be I-70W to I-435 North to I-29 North.
I'll plan on meeting up with you and if possible I ride with you through town.
I can't remember but did you ride through KC before on the Run for the Wall?