Whether you want to stop, and how much time you want to spend depends on what you like to do, but here are a few Route 66 quick stops in Oklahoma. You can research them and decide for yourself whether any are of any interest, and how much time you should allow. The Canadian River bridge is just a bridge, but it is long and narrow, and gives an idea of what drivers dealt with "back in the day."

Clanton's Cafe in Vinita, Oklahoma - Best chicken-fried steak in the country - a true taste of Oklahoma

Will Rogers Museum in Claremore, OK

Canadian River bridge between El Reno and Hydro

Red Rock Canyon State Park near Hinton, OK

National Cowboy Hall of Fame and Western Heritage Center in Oklahoma City

Oklahoma City Bombing Memorial

Philbrook and Gilcrease Art Museums in Tulsa

As for Grand Canyon and Vegas, if you've already seen the Grand Canyon itself, then I would say that your next trip there should be to spend some time hiking, exploring and visiting the North Rim, which means that you probably won't have time for that on this trip. Vegas - Well, Vegas is Vegas - depends on how much you like bright lights and gambling.

In Arizona, Route 66 takes you to Flagstaff, which is nice, but a good side-trip would be to drop down south out of Flagstaff and visit both Sedona and Jerome. Sedona is well-known, but Jerome is just an interesting small town built on the side of a mountain. Sort of spooky to drive through it, but interesting that people chose that spot to build a town. I think it was once an old mining (silver?) town.