A couple of things to think about. The first somewhat addresses your question about ride. The lower pressure in the tire, generally the better the ride, all other things being equal, but they rarely are. A tire, or an airbag in a suspension for that matter, acts as a progressive spring where the amount of force needed to compress it gets greater as the compression of the tire or air bag increases. This is one of the reasons that you see relatively high profile tires on most street vehicles, it can compress a log way which makes the ride better and also protects the wheel. It also aids in compliance with the road surface. If you intend to keep the diameter of the tire the same, and you should, you will need lower profile tires. This leads to different problem with potential rim damage if the tire compresses to the point that it contacts the wheel, especially on a pot hole and also a pretty good chance of tire damage as it will be pinched between the pot hole and the rim. If you don't keep the diameter the same your speedometer will not read correctly. Another thing to think about is fender well clearance with larger wheels, especially larger in width. The tire store will try and put an adjustable jig on the tire to measure fender clearance, this may not work a full suspension compression. Just some things to think about.

Not mentioned either is whether this truck would be your tow vehicle, if you are RV'ing with some kind of trailer.  If it is your tow vehicle, then you'd also have the additional weight from the front part of the trailer, either at the bumper hitch or directly over the rear axle with a fifth wheel.

I guess another question would also be if one wanted to "look good" while sitting at the side of the road waiting for roadside assistance?

Personally, I'd stay with regular wheels and regular tires.  I'm not even sure that one's 20" tires would handle the weight load from a towable RV.  That would need to be checked out long before one "modified" the truck.

Terry

Since you brought this question to an RV oriented forum... the answer is probably yes. If you are only towing a small trailer then you "probably" won't have any issues other than the ride is likely to be harsher. If you plan on tow a trailer that tests your factory GVWR ratings then as others have said.... don't. This is one time when it is better to be safe rather than to look good. The ratings on any truck are based on the weakest link... if you go with taller wheels and lower profile  tires.... you are inviting a negative outcome. 

You don't say what you will be doing with your 2500, what you will be carrying or towing... or what tires you intend to put on those wheels. All relevant to this conversation.

Food for thought.