8500# as was suggested will put you over or very very close to the limits of the truck. Especially, when the truck is full of gear and kids.
A good range would be 5-6K loaded trailers. These will usually be in the 22-24 foot range. Lots of good options with bunks in this size/weight. Pour through the forums and educate yourself about weights - trailer dry, trailer loaded, truck gvwr, truck payload, etc, etc. You'll be a pro in no time. You've already done the hardest part - asking for help and realizing how to do it right. You're ahead of 95% of the folks you'll run into in your travels.