89,000 miles is not too many miles and since the van is relatively new, I would do as has been suggested, perhaps take it to a Dodge dealer unless you have a prefered, trusted mechanic, and get the oil change, belt(s) checked, hoses, etc. Tell them you are about to go on a long trip and want to take care of anything that should not wait untill you get back. Be wary that having told them about a long trip, they may recommend items that really don't need fixing right away. If confused by their advise, take it to another garage for a second opinion.
With that mileage, one thing I would recommend having inspected is the serpentine belt. This belt runs everything under the hood that is powered by the engine (power steering, power breaks, alternator, a/c, etc.). The cost of replacing the belt should be about $100.00.
Also, if your van uses a timing belt and it hasn't been replaced, it is way past due. Most imports use a timing belt that wears out about every 60,000 miles. This belt is inside the engine and if it goes, the engine could be seriously damaged because the parts in the engine that are synchronized would no longer be in sync and would start coliding into each other. The cost of replacing it would be about $250-$400. However, just ask if your van has one, most domestic brands have a timing chain instead of a belt. Typically, the chains aren't likely to give any trouble with your mileage.
Having given all of this advise LOL, I am in no way a car care expert. There may be other items that need to be serviced and only a qualified service technician can determine if there is, but your van should not be past its prime by any means so you shouldn't have to worry about car trouble unless there is something you know about, or if it has started giving you problems.
Have a great trip!
