Trip Denver,Co to San diego with a stop in Las vegas

Traffic in CA is TERRIBLE but it's worth it. Also, keep in mind that if you have a towed you are pulling the speed limit is 55 on all roads so you can't be running the 70 MPH speed limit on most of the Interstates.
As you come down the 15 into the LA area you will want to take 215 and reconnect with 15 on the other side. There is little mileage difference but you have a better chance of not being stuck in traffic.
Now, out of Phoenix heading for Vegas you are going to want to take 60 (60/93) through Wickenburg to 40 and then 93 into Vegas and by the Hoover Dam. The new bridge does not give you any views of the Dam so if you want to you can divert and drive across the dam or stop on the NV side of the dam and take your car down for a look see.

In Vegas try the Oasis RV Resort at the south end of the strip. Reasonable and great pool area. Easy access off I 15..

Appreciate all the help. Have a couple of questions

Do we stay on I215 thru San Bernardino to I15 or cut over to Ontario and then to I15

Someone said that the Cajon pass is bad with construction and should not be attemped on a Friday which is when we were figuring on being there on our way to Las Vegas

Having never driven in Californis ( only seen Pictures ha ha )I'm wondering how bad the traffic is on this route between Can Diego and Las Vegas

Keyteg1 said:
"Also remember that California does not allow bringing fruits and they might check your coach for moths. The agriculture check station is East of Barstow, but they are building new one close to the state line. Don't get upset if they hold you there for some time. "

I run in and out of California all the time and yet to have seen a RV being held.

Yes, they ask about fruits, etc but it's fairly fast.

Could you explain "they hold you there for some time". Did it happen to you?

KOA no longer runs the RV park at Circus Circus but it is still open at about 1/3 its former size. Call the hotel and all is well.

In Las Vegas, if you plan walking on the strip the Circus Circus RV park has the best location.
Price-wise KOA (I think it is called Sam's) RV park offer best rates.

As mentioned above, the Circus Circus KOA on the strip is closed. They moved their KOA license to the Sam's Town RV park which is no where near the strip. We had our van broken into twice at Sam's Town and would not return in the future.

The Circus Circus RV park has closed.

You will want to avoid the Cajon pass at all cost on a Sunday when heading south and on Friday going North, they are doing major road work and it has been a mess. You will find Cajon pass just south of Hesperia on I-15 this pass will drop you down in the San Bernardino area. The pass is only a 6% grade you will be fine on that.

In Las Vegas, if you plan walking on the strip the Circus Circus RV park has the best location.
Price-wise KOA (I think it is called Sam's) RV park offer best rates.
Mind the dining on the Strip is extremely expensive and if you go to satellite casinos, they offer lower prices.
Before reaching Las Vegas, consider overnight stop at Valley of Fire. It is really worth it.
From Vegas to Diego there is not much to stop. In Baker you might stop to take a picture of tallest thermometer in the World.
Few miles East of Barstow you can visit Calico Ghost Town -western park.
The route is stuffed with up to 17 miles long grades, so if you plan to take it midday, make sure your cooling system is in perfect condition as 100F is cold day there even in September.
Also remember that California does not allow bringing fruits and they might check your coach for moths. The agriculture check station is East of Barstow, but they are building new one close to the state line. Don't get upset if they hold you there for some time.

Lovely drive, you'll have a wonderful trip. In Albuquerque don't miss the Childen's Park. Sure it says children's but adults love it too. Across to Flagstaff, but I would go a bit farther and base in Williams, about 15 min west. Enjoy Circle of Pines KOA, stop at Bearazone drive through animal park, and the Grand Canyon is 60 miles straight drive north. Then cut up the 93 or 95 to Las Vegas, we enjoy the Oasis RV park, although Sam's Town (now a KOA) is pleasant. All of this driving is through mountains and deserts on good roads (as good as they get with the current non-existent level of road repair). None of the mountain climbs are stressful in a well cared for RV. Las Vegas to San Diego is desert with two long mountain grades, Baker grade (not to bad but it is a place where cars in poor condition overheat) and the Cajon Pass (west of Victorville, a very long steep grade often with strong cross winds) You can do it but you won't go fast. With all this said, if you have time, I would go from Denver down the 25 and then across to Durango/Mesa Verde, and down through Monument Valley spending a night at Goulding's. Then on to Flagstaff and Williams and Vegas.
Have a great trip.