Need advice for shopping for a car hauler trailer

I am getting married next fall and my Fiance' absolutely wants my Duster in our wedding. :blob:

The thing is, We are getting married in Michigan and we live in St.Louis, Mo. It is about an 8 hour drive. Since driving the car is out of the question, I am going to be needing a trailer to bring it up there.

I would like to be able to use this trailer for everything from hauling our 4 wheelers (atvs), The Duster, and our old V10 if it ever breaks down and I have to go get it.

I was thinking of buying a 12k 20' dove tail since the heaviest/largest thing I ever plan on towing is our 2000 Ram 2500 V10. From what I remember it weighs roughly 8800lbs. I don't want to get a 20' and wish it was an 18' and I don't want to get a 12k and wish I had a 10k.

For you guys who tow car haulers and transport cars alot, What kind of trailer would you use? Is a 20' dove tail rated at 12k too much? I don't really want an enclosed trailer.