First off lets get the gorilla out of the room (brand does not matter) as people are "very loyal" to the brand they will suggest. So next issue is weight the coach you own right now is just under 10,000# GVW so you will need the biggest 1500 you can but to make this work!
So the item is since you claim you are new to this most people keep the coach they own right now for maybe 3 to 4 years, then they get something else, might be bigger (Family things, toys change etc
so just to give yourself a small window of safety you should get a 2500 truck, if there is the SMALLEST idea that you might upgrade to a larger coach you have to get a 3500 series truck.
SO you need to sit down and think real hard "what am I going to do in a year or two or three with rving with the toys you have, how much traveling you will be doing" and then that will steer you to the correct truck.
Now the question I need to ask, you did not say what series the suburban is, and why you do not feel comfortable using it?