First off, let me share an opinion with you.....

I HATE tow dollies
They are used a lot, but they are less than ideal ways to transport your baby.
Especially the rental ones.
I have had more than one bad experience with tow dollies.
One cost me a lot of money fixing my stuff.
(not to mention the laundry bill )

Go rent a good trailer that has good brakes and make your trip nice and slow and get there in one piece.
Jeff