Nell,
To be safe in the mountains where you live, you need at least a 1/2 ton  full 
size pickup. It should have a towing capacity of at least 5,000 lbs and  
preferably a factory towing package which gives you the proper gear ratio,  
cooling, brakes and tires for the job. Brand is unimportant, but I would  recommend 
a V8 engine. All manufacture's recommend the automatic transmission  with a 
special cooler for it. 
There is usually a sticker from the factory located in the glove box with  
factory information which contains paint codes and everything that was installed 
 when the truck was built. The door jam on the drivers side has a sticker 
with  the GVW (gross vehicle weight) and GVWR (gross vehicle weight rating) The 
GVWR  is the important one you need to look at. GVWR includes the weight of the 
truck,  the fuel, passengers and the maximum amount you can carry or tow.
 
Rummy