I shall assume you are talking about a travel trailer (TT) and are using a weight distributing hitch, Class IV or V.
First thing to consider is the rating of your receiver and your ball mount. Class IV will handle a 1200# tongue weight and tow 12,000#. Class V will handle 1400# and tow 14,000#. [The figures are from Reese Products and weight distributing is required.]
Secondly can your truck haul the load? If your 2000 F250 has the 7.3TD and a 3.73 rear end it will haul 10,000#. Do your self a favor and limit that to 9,000# to allow for hill country and aging truck. If you tow in the west keep it to 8,000# to allow for long long steep upgrades at 6000-7000 feet above sea level