I love this idea, would you recommend staying on or off property first or does it really not matter?
I would start with onsite, then move. With two value rooms, you would have 500 square feet of living space. After the excitement of the first few days of your trip wears off, having some space will make the rest of your trip much more enjoyable.
For example, A 2 bedroom at Wyndham Bonnet Creek is 1,200 square feet, and costs much less per night than two value rooms. It has a full kitchen and a washer and dryer. That resort is next door to the Disney Caribbean Beach resort, so you are not miles out of the way.

We have a 1 bedroom Island Suite which sleeps six, at considerably less cost than even the discounted BWI room. I wasn't sure of our dates so we booked that in case we can't make for those first couple of days.
) so two rooms just didn't appeal to us as well as one big one.