It should be stamped on the hitch but it may be covered with someones paint job. It could be 1 7/8", 2" or 2 5/16".
EBay is the best site online that I would choose to find a used trailer hitch. They have online auctions on anything and everything and the highest bidder wins.
Craigslist can usually provide you for many postings about a trailer hitch for sale in your local area, and often at cheaper prices than national trailer dealerships and such.
If your jeep does not have a factory trailer hitch installed then you would look one up online, in a catalog, or go to a hitch dealer, and find one make for your jeep. If you have the factory hitch receiver then you are most likely looking for what is called a ball mount. My 2003 liberty with factory hitch receiver requires a 2 inch ball mount. That's the outside size of the square tubing. You will also need the 'ball' itself. The size required is determined by the 'hitch' on the trailer or device being towed. 1-7/8 and 2 inch balls are common sizes. You may also need a T-One adaptor to hook up the trailer lighting. Anyone competent at Napa, AutoZone, CarQuest, etc. should be able to help you out if you need a personalized touch.
Colonial Airstream is the first place to look. They supply all the accessories available for Airstream trailers. On this site you can find the right model to fit your trailer. With that in mind to get a bargain try secondhand sites such as eBay.
If you are looking to rent a trailer, the rental place can help you find the right hitch, Uhaul has a form that will tell you what hitch you need for your vehicle http://store.uhaul.com/hitches.aspx?src=hitches If you are buying a trailer, the dealer should be able to match your vehicle to the right hitch.
There are many places online can you can research to find a weight distribution hitch for your trailer. There is a place called Reese Hitches where you can find one and of course Amazon sells just about everything.
Try U-Haul they may have a kit with instructions
http://fawgame.com/?rf=41726368616e67656c this is maybe
The heaviest gooseneck hitch for a Ford F250 Super Duty I could find was 30,000 pounds. I found this hitch at Hitches4Less.com - http://hitches4less.com/goosneck-trailer-hitches.html
If you're looking for a cheap trailer hitch, then check out www.uhaul.com. They've been around for many, many years and are very reliable with great prices.
Retailers have their own return policies. You will have to contact the person/company that sold the travel trailer to you to find out if you can return it.
well you by a hitch appropriate to the tong of your trailer (standard is 1 and 7/8 inches). you then mount it on your rear bumper, it took me awhile to find a hitch that would fit in the whole on the bumper, but if you go to a mechanics he can drill it out and make anything fit.