I don't have any comments regarding hitch size, but I do know where you
can get a good deal on Drawtite Hitches.
I bought a Drawtite hitch for my Subaru Outback that's good for 3000
pounds early this year. All of the local people wanted about $180 for
the hitch and I found it on the internet for around $100 with shipping.
I the link to the site is:
http://www.miley.com/drawtite.htm
They paid the shipping and were very helpful and responsive. Because
the hitches are so big, heavy and indestructible, they just slap a label
onto the hitch and mail it as is with a box of hardware taped to the
Hitch.
I don't know about the Aerostar, but mounting the hitch on my Outback
was an almost trivial job -- local shops wanted $50-$75 -- and it took
me about ten minutes after I got all of the tools together. It mounts to
the frame and uses the towing hooks for one of the attachment points. I
only had to drill two holes. I still remember the bloody knuckles of
mounting the old bumper hitches......
I have no financial or other interest in either drawtite or Miley....
Regards
Rye