Brux,
I see you are our past home state of Michigan. What a great place for camping. You should include some guidance for the group on how you intend to use your new rig. It will help guide us along.
If your a weekender, anything you can do to extend your season in the North, is a good investment. If you're a full-timer or a snowbird, the list and pricetags can change and grow exponentially, with items like Satellite TV, Wireless Broadband equipment, washer/drier, new truck, etc.
Many of the 'items' I'd recommend are projects, not just pieces and parts to be procured. Example, replace the mechanical thermostats with digital / programmable stats. Projects are hard to recommend due to your needs and preferences, and your budget and abilities.
I'd hate to guess how many thousand years of widely-varied experience you can find just on this users forum. I'd recommend using the search utility of this site and ready some of the posts.