That sounds like a really nice trailer, who's the manufacturer? Regardless, check the tires and always keep them aired to the max as most manufacturer's use subpar tires and it's one of the biggest complaints. My trailers run on the highest load range LT truck tire I can get and always outlast what I was getting from normal trailer tires.
On the subject of a WD hitch, you can get by without one but they don't hurt so why not. Craigslist will be your friend for that purchase, there isn't much reason to go new as most people don't use them long enough to wear them out.
Tongue weight is very important, make sure you have enough! Too much is better than too little and tongue weight is what causes the tail wagging issue you'll hear so much about. To put it in perspective, I'd rather take a regular hitch with the correct tongue weight over a WD hitch with the incorrect tongue weight.
If your trailer is out-of-whack, a brake controller that will allow you to gradually apply the trailer brakes without applying your truck brakes (some of them have a slider), will bring any swaying or weird trailer action back into control.
Make sure the wheel bearings are greased as are any other zerks, I've seen factory hubs that are almost dry. If you end up needing any trailer bearings, races, etc., Tractor Supply has just about everything and Lowes usually at least has bearings. Hopefully it doesn't come to that though.
Also, a high lift Jack is great for changing flat trailer tires and MUCH quicker than a bottle jack, I'd have one of those along.
Last bit of advice; Buy a spare tire from walmart and keep it out of the elements. If you don't need it and make it to your destination without a flat, you can take it back to the store for a full refund.
Hope these tips helped and don't hesitate if you have any questions!