I've been hauling a trailer behind my 87 Westy for 3 years now . It's great
i haven't noticed any major difference in the way the van handles or gas
millage, and the extra room is wonderful. The trip to Mexico last winter was
over 10,000 Km , there were a few times I got in trouble and had to back up
in difficult situations but it all worked out. Once I had to take the
trailer off and leave it in driveway then found a pace to turn around in the
narrow street and went back to get the trailer. The trailer I have was made
in the mid 70's its all fiberglass and fully loaded you can move it around
with one hand. The big drawback I see with a trailer is, you have a tendency
to take way more than you need.
  As far as backing up goes. I can't see my trailer in the rear mirror but
someone mentioned to me to watch the side mirrors and when you first see the
trailer in either the L or R mirror turn the wheel towards that mirror to
keep backing straight. It works well
 Its really nice to leave everything locked in the trailer at a campsite and
have the empty van to explore with.

--
Twenty years from now you will be more disappointed by the things that you
didn't do than by the ones you did do. So throw off the bowlines. Sail away
from the safe harbour. Catch the trade winds in your sails. Explore. Dream.
Discover. ~ Mark Twain