The road from South Fork to Creede (149) is virtually level, and you'll encounter no problems. We've driven it dozens of times. The scenery is beautiful along the Rio Grande River. We live in Pagosa Springs. If you have some time in Creede, the Creede Repertory Theater is renowned for its performances - the current show is supposed to be particularly good and has received great reviews:
Creede Repertory Theatre, Creede, CO
And yes, highway 160 from South Fork over Wolf Creek Pass is the "steep pass" made famous by C.W. McCall in the song, "Wolf Creek Pass". It's not as terrifying as he made it out to be, but exercise due caution coming down. Many truckers wish they had.
You'll find that leaving South Fork heading west on 160, you will do some climbing on good roads to the top of Wolf Creek, alongside a beautiful stream and past two RV resorts with camping alongside the river. This section of the road was recently rebuilt, and is easy to travel. Just before the tunnel is a pullout with restrooms. Once you go through the tunnel heading west, you'll find a divided highway, with two lanes heading up the mountain - plenty of room for slow vehicles. Watch for small rocks that have fallen into the right lane - happens once in awhile.
Once you see the ski resort (Wolf Creek), you'll be less than a mile from the top of the pass. There's a turn out (left side) at the top if you'd like to stop before heading down the mountain, as well as some wide spots on the right side of the road. You can also stop at Wolf Creek Ski area, but it's on the left side of the road at a fairly sharp right hand turn.
You'll have a 4-lane road nearly all the way to the bottom, although there are a few spots where it's only one lane going down. You'll come to a very sharp switchback with a fantastic view (better left to passengers) as you get closer to the bottom of the mountain. Since you'll be towing, I wouldn't advise taking the turn out - it's a bit narrow.
Once you've reached the bottom, on your left is Treasure Falls - a great spot to hike up to the waterfall if you need a break. There are pullouts on the right side of the highway at this point if you wish to stop. The Treasure Falls parking lot may not be large enough to actually try to use it in an RV, especially towing - and the pull outs on the right side are close to the Treasure Falls parking lot.
There are two "runaway truck ramps" on the way down the mountain - you'll undoubtedly not need them, but they're available. Do be careful - gear down low, put on the flashers, take your time, and enjoy Wolf Creek Pass. Beautiful place!
Once you're off the pass, the rest of the trip through south western Colorado on highway 160 is a piece of cake....
Let me know if you have any more questions.