Rte 160 in Colorado

I have a 37 ft gas Georgia boy landau with triton v10 pull 12 foot enclosed trailer

Yes, Cumbres Pass around 10,000
Your best bet is to take 160. Just be aware of down grade and take it slow and easy, stopping at some of the pull outs.
Knowing what kind of rig would help to give advise.

Any steep grades along this rte.

Well I don't know how everyone else feels about this suggestion. Last year we took Hwy 285 out of Alamosa to Antonito west on 17 to Chama New Mexico then 64/84 which you finally take 84 to Pagosa Springs then back to 160 west. We stayed in Chama for a night and enjoyed the railroad yard etc. We also dieseled up there before we left the next day. I don't know how much it was out of the way to by pass 160, but it was a beautiful ride. Just my 2 cents. Check it out on a map and you will see this route. Be safe and enjoy....

Are there any other rte. That are not as steep?

Travel it a lot. Respect it for what it is. The roads have been much improved since the song was written, but still a good steep grade. Have your passenger get the camera ready down the west side of Wolf Creek into Pagosa! Some of my favorite views.

US 160 is a virtual pipeline for RVs and trucks across southern CO. Wolf Creek Pass is much steeper on the west side than the east side. So the direction you will be going you will have the easier climb, but the steeper downhill side. But there are two lanes going down the west side so you can stay right going as slow as you want without holding up traffic. Beautiful drive. Enjoy.

And there are two runaway truck ramps going down if you need them. :B

East of Pagosa Springs, there is a fairly steep down hill coming from the east. Down shift in to lower gears. Take care of your brakes!
Otherwise good two lane highway.

US 160 is a fine road with one major and a couple of minor passes between Ft. Garland and Cortez. The road is a US highway and is the major east west road between I-40 and I-70. On Wolf Creek Pass, the roadway is four or three lanes, depending on your direction. (The other passes are not a big deal, mainly a couple of miles long with climbing lanes in each direction.) The main thing us locals know is that you pay absolute attention to the speed limits, especially in a motorhome, and you use your gearing and exhaust/engine brake on the descents. I usually count the number of times I need to tap my brake on the descent of Wolf Creek (and by that I mean just for a second to get the speed back down under 45 mph). I try to keep it under ten times for the whole descent. A trucker went over the cliff at the next to last westbound switchback the other day because his brakes had overheated. He passed on two runaway truck ramps. It cost him his life.