Is the Red Rock Canyon scenic loop drive worthwhile? I am not interested in hiking, just the drive and brief stops at scenic look-out points. How much time does it take to do the round trip from the Strip, around the loop and back?

Yes everything about Red Rock is worth it
The drive is about a 13 mile loop,one way,you just drive along,looking at the Rock formations and the desert,sometimes wild burros and snakes! It takes about 30 minutes to get there,depends on if you get out of the car and walk around as to how long you will be there.
It is really worth a break from the Strip and hotels to go out and see the desert in such a nice way.
Take a picnic and make a half day out of it!

Entirely agree with Scarlett. My wife and I just got back from LV from where we took a 4-hour-long trip to Red Rock Canyon. The scenery is wonderful, and you will love it. Enjoy.

Definitely worth the short drive from the strip to see Red Rock. If you feel more adventurous, and feel like a bit longer trip, then see Valley of Fire Park which is northeast of Vegas on I-15. Red Rock Canyon is a miniature version of The Valley of Fire.

I took bus trips with a guide to Red Rock and the Valley of Fire. The valley was much better and very unusual. I would recommend a drive to the Valley instead if you can. Or do both - they are worth it! I believe the Valley of Fire is doable in 1/2 day if you don't want to stop.