Hi,
I am new to horse trailering and recently purchased a 2004 Dodge Ram 1500, auto with tow/haul, 3.55 axle, 4.7L engine to pull my two horse TB aluminum trailer (7000# Gvw and aprox. 2400# empty, 400# tongue wt). I pulled it from the beach to the mountains with one 900# pony. It pulled easy except for one stretch of about 2 miles up the mountain where it reved up to 4000 rpm. Is that straining the truck?
Since then, I have purchased the same type trailer but it has a 3 foot dressing room. It weighs aprox. 3000# empty with a 600# tongue wt. It seems to pull a lot heavier than the first one. I will be hauling a horse (1250#) and a pony (900#) plus assorted tack, hay, water, etc. mostly near the coast although I would occasionally like to make a trip to the mountains.
I do plan to add a weight distribution hitch. I think the truck is rated for about 6400# Do you think this truck will do the job?

4000 rpm's not bad for a gas engine, red line is around 6000. The Hemi (5.7L) would be nice, but if you stay under 6000#'s loaded and on flat roads, you should be fine. Same auto tranny as with the Hemi. I wouldn't haul with that setup every day though.