We rented an RV, not a trailer, in Orlando in 2004. Our son was 6 months old and we didn't want to tent camp with him. We drove down from TN in our car, rented the RV offsite (I can't remember which company, sorry), and drove the RV and our car to the campground. It was not exactly cheap, though. I don't remember the exact cost, but I think it was more expensive than staying at a value resort onsite. We did it this way because we had family staying in the Fort with us.
I would recommend it if you can find the type of equipment you will be comfortable in. The campground has so much to offer in terms of activities and you can really relax there.
Good luck with your decision.