Well, there are 2 ways to adjust alignment on these Vans, either shift the subframe, or Slot the Strut by grinding the hole bigger, and shift it.
I've done combination of both before.

 

I have the same problem wih my 2011 Grand Caravan pulling to the right at highway speeds. This will happen on a two-lane road or in either lane of a divided highway. Currently have 37,000 miles and will soon replace all four tires due to excessive outside-edge wear. The wear is caused by the rear-tires being out of alignment. I first noticed this (dealer service actually notified me during oil-change) around 20,000 miles. I asked the dealer to check alignment in the rear and they wanted $89.95 just to put it on the rack. I wanted it checked under the 3 yr. 36,000 bumper to bumper warranty, but they said that any repair was an "adjustment" of the "non-adjustable" rear alignment not covered under the warranty, or it was most likely I damaged the alignment by hitting something. Pissed, I complained to the owner who agreed with me about the warranty coverage. They supposedly adjusted the rear alignment by adding shims. The van still pulls to the right and hopefully the new tires will help. I just hope that the rear isn't still out-of-whack as I want these new tires to last much longer. My dealer just got a large shipment used 2011-2012 GC's and I've looked at the vans on the lot with the original Yokahama tires and they almost all had uneven wear around the outside edge of the rear-tires similar to my problem.

 

Those Yokohama tires wears out on outer edge A lot faster than the center, and they last about 40k miles most of the time. this is just the Tire's characteristic.

Also, Alignment is only covered for 1yr/12k mile like the brake.
Some shops like Firestone or Sears auto offers free alignment check if you want to do it. Yes, you could align the Rear by adding shims. But there are really no purpose on going thru the headache.

 

I had the "toe end" set @ 0 an solved the pulling problem . I now have 12,600 miles an all is well .
I also have 4 wheel perfect brakes "no problems " like new top pedal .
All though it ran like a dog "sluggish "till 12,000 miles now it will move ????? Lovvorn