There certainly is a great difference of opinion on this topic; get ready, you are gonna hear from 'em all.
I have a Jeep Liberty CRD, 335 ft-lbs torque, rated to tow 5,000 lbs. My TT is 21 feet, 5,000 lbs gross/3650 dry weight. And based on my experiences with this set up, I'd say you'll be fine with the Captiva or the Surveyer. The Keystone leaves a little less cargo capacity than I'd like to see, but it might be fine. I think your tongue weight capacity is too low, however. You might have to do something about that.
And yes, I'm sure there will be folks horrified at my rig, just as they will be at your proposed ones.
