From Colorado Springs area, to avoid passes I would take US 50 west from Pueblo to Poncha Springs, south on US 285 to US 160. You do go over Poncha Pass but it is nothing to worry about. And it misses La Veta Pass. La Veta Pass is not bad, but going west bound the climb is a little longer and harder than east bound.
Going west on 160 you would cross Wolf Creek Pass. As mentioned above going west bound is the easier direction. The climb up the east side is not bad. The descent down the west side is steep and long. But the highway is very good 2 lanes each way all the way down so you can go as slow as you want.
If you would really rather avoid it altogether, you can take CO 17 where it splits off from US 285 and go straight down to Alamosa. From Alamosa pick up US 285 again and continue south to US 64, take it west all the way up to Pagosa Springs. That bypasses Wolf Creek Pass altogether. Adds around 80 miles or so, but may be worth it to you.
I would add that US 160 is a virtual RV pipeline during the summer months with RVs of all shapes and sizes constantly going both directions. Generally no problem unless you are at your weight/power limits.
