Welcome BScott,
Which of the Keystone RV's are you interested in? A travel trailer or 5th wheel?
Some of the larger, higher-end, Keystone 5th wheels may be better suited for full-time living, but unfortunately most all of those would require a 350/3500 series truck & possibly even a dually. Generally speaking, of course.
Whether buying a travel trailer or 5th wheel - in addition to your wants/needs in a floorplan, features & options, etc. - insulation R-factors are also very important to consider & compare... especially when living in a northern/southern location.
Winter weather has been quite the topic of conversation lately
& there's some good advice here if you'll read through the posts.
Terri [& DH Kevin]