Don't be too quick to make any modifications on your new rig. You really need to use it, drive it, test it out for a while so you'll have a better understanding of what you REALLY need to do, fix, or change.
This goes for not only the suspension and drive train and everything essential for driving on the road, but also for everything inside the coach where you live.
You may find, (as stated above), once you get your gear and all items loaded, including water, propane, and fuel, you may find the rig handles quite different.
And the other suggestion above, use it on small trips first, is absolutely sound and solid advise. Learn your new rig in very small bites. Don't try to swallow the whole thing all at once or you'll choke and suffocate yourself. Take it one small step at a time. The first step is simply driving it around the parking lot at the dealership. Then driving to a parking lot where you can do some initial practice backing up and turning corners, figure out how sharp the rig turns and how much swing the end requires. Do this first, and then some short runs ... like ... use it to run to the grocery store or maybe some other errands. Little baby steps, over very, very short periods of time will do you more good than anything else.