Don't know about the Silverado and others you mentioned. When we upgraded from 1/2 to 3/4 ton, both with long box, our new 3/4 ton has the supercab which makes the overall length about 20" longer. Holy smokes, the extra length is so much harder to turn around corners and park in parking lots. Never would have guessed. Makes it much more interesting getting the truck and trailer around some corners! And our trailer is only 29'.
IMHO, the extra overall length of a tow vehicle is definitely something to think about before committing.
If shopping for a new RV, the end of the camping season is always best price-wise. They don't want them languishing on their lots all winter. You can squeeze them a lot harder then. Beware of the model year they are flogging. An RV could really be a 2012 model that has been sitting for a while. Then when you start camping in 2014, it's already 2 years old before you've even used it. Some makers start bringing out their new model years starting about now. So compared to other RVS, a 2012 model that you just bought could quickly look like a 3 year old one. Not a big deal if you intend to keep a long time, but if you ever decide to sell it not too long after, it will affect the market value.
Next best time I think, is around Feb. or so before the season is really gearing up. Dealers want to start getting new orders going to get them in a couple of months later. Many RV shows are in Feb. and are a good way to see what's coming up. Better deals available then rather than waiting another 2-3 months.
Also keep in mind that if buying new, dealer servicing for warranty will be important. Local dealers don't want to work on new units purchased anywhere else, esp. several states away. Also, looking into dealer "quality" is a good idea. They range from awful to outstanding.
