First...Welcome to the Forum.
Now, for the hard facts: That is a a 33 foot trailer that will have a tongue weight of right around 1000 lbs when you are trip loaded.
It's not about what your Expy can tow but more about Payload. Subtract the 1000 lb. tongue weight + the weight of your hitch + the weight of the family and the dog and all the gear that you load in your Expy from the Payload rating on the door plate.
Having had an Expy (P rated tires, soft suspension and short wheel base) I suspect that you will be marginal or worse.
Sorry to be so negative, hopefully others will chime in with a brighter outlook.
Any, good luck with your new adventure.