Sorry, but personally I wouldn't even consider what you are suggesting. For starters go to this address: http://www.fordvehicles.com/assets/p...F15_towing.pdf
The figures are for 2008's but should be fairly close to 2004's.
Given the limited information available from your previous posts, I would say that you would have a marginal situation, at the very best.
Also note that it is common to derate the vehicle manufacturer's figures by about 15%, as a safety factor. My suggestion is to take your empty truck with a full tank of gas, hook up your empty trailer, and take them to a commercial scale to have them weighed - the truck,the trailer and the combination of the two.
Next add the weight of all potential passengers (including yourself if you were not in the truck when it was weighed,) pets and all other cargo which you will carry either in the truck or trailer. (For example: anything that will go outside under the awning, cookware, bedding, clothing, food, canned or packaged goods, water in the water tank, hoses, gas in the propane tank, all the stuff that goes in the bathroom or under the kitchen sink, bikes or other "toys" - and the list goes on...) It is very easy to underestimate the weight of these items or to forget some items. How about those extension cords, the electric heater for those chilly mornings, the grill you just have to have for those hamburgers, boards for leveling the trailer? See what I mean?
So... I would suggest adding a large fudge factor. Also, don't forget that your truck is now about four years old and may not be possessed of the same vim and vigor as when it was new.
By the way - is your trucked equipped with a tow package (Heavy duty radiator, transmission cooler)? Manual or auto transmission? What is the axle ratio or "rear end"? So many questions!
Tongue in cheek aside, you might be a lot happier with, say, a 250, with the towing package, a 5.4 and a 4:10 rear end.
I hope this helps to keep you and your family safe.