I appreciate any suggestions:

I love my truck and here's the situation: 

Family just purchased a big 5th wheel rv (GVWR 12000 lbs-ish).  We also have a 3 horse Cimarron non-living quarters gooseneck (GVWR 10400).  My sister has the Ford F-250 Diesel truck that will pull all we have.  We have 3 big quarter horses easily weighing 1000 lbs each and a ton of gear that goes in the trailer (feed, luggage, tack etc). 

So, if I want to go rv'ing for the weekend - borrow my sisters truck.  But will my Dodge 1500 Hemi pull the horse trailer safely?  I'm toying with getting both trailers weighed just to be sure but am still worried about braking etc with the smaller truck.  We travel a good bit with the horse trailer and hurricanes in the last few years have taught us some good lessons - be prepared. 

Again, any advice is appreciated...

Ellen

The safe answer is no, but you need to know several things.

1. What is the tow rating for your truck
2. What is the UVW(unloaded vehicle weight) of my trailer.  The GVWR has very little to do with the unloaded weight.  It is what the axles are rated to carry.
3. What is the total weight of my horses, gear, food, water...

When you know all of that, you will have a better idea of how much you will actually be towing and then can compare that to your tow rating.  My guess is that you will overload the truck.