You will be able to tow the Colorado. Yes, Chevy lists the GVWR at 5,900 lbs (spec sheet HERE
) but you, in all likelihood, will not be loading the Colorado to its GVWR when you are towing it.
The GVWR is the maximum weight that Chevrolet says should not be exceeded (either while being towed or driven down the road).
You more likely will be closer to the curb weight which is 4,374 lbs (assuming the maximum which is a Z71, spec sheet again HERE
). The curb weight is the the weight more closely associated to the actual weight when the Colorado is not loaded with cargo or people.
The GVWR of your 2011 Winnebago Access 31NP is 20,000 lbs. with a GAWR of 14,500 so the towing capacity is 5,500 lbs (20,000 - 14,500 = 5,500). HOWEVER, the hitch is rated at only 5,000 lbs. so in reality, your towing capacity is limited to the current hitch rating or 5,000 lbs. These figures are directly from Winnebago ...the 2011 Access brochure --go HERE
So on paper, you will be able to tow the Colorado as long as you keep its weight under 5,000 lbs. and you are pretty close to it so make sure you are not loading any cargo, or at least very little cargo, into the Colorado as it is being towed.
And, as the previous poster has mentioned, your tow bar is rated for at least 5,000 lbs.
It doesn't mean that it will be a comfortable tow as, again, you will be very close to the limits pertaining to the 5,000 lb. hitch rating limit and the GAWR so you more than likely will "feel" the weight of that toad when traveling over mountain passes, etc. It will help if you keep the weight of the coach substantially under its GVWR. You may want a hitch and welding shop to check to make sure that Winnebago engineered the hitch correctly or even upgrade it if necessary ...again, I don't really like being that close to the limit.