1) Get the coach weighed and look up the inflation charts for your tires and the weight carried by each axle.
2) Get a four wheel alignment done by a very qualified shop.
3) Add a rear stabilizer to your rig (Tiger Trak makes a good one)
4) Install an airbag system if you don't like how the shocks affect the coach. (Kelderman is a good one)
5) Some people have had good luck with steering stabilizers.
As for noise, there are plenty of acoustical insulation products you can apply to the underside of your dog house and firewall that should make a noticeable difference.
A diesel pusher is nice too if you'd like to upgrade.