Hi Richard,
It depends on how comfortable everyone is sharing close quarters. Certainly, the value resorts offer much less elbow room in their standard rooms and only double size beds. If budget is a number one criteria, opt for two rooms at a value resort.
Moderate resorts at Walt Disney World will provide a little more space and queen size beds in most rooms. Caribbean Beach Resort, however, still has double size beds in the rooms.
Deluxe resorts will give you more space and queen beds plus in many rooms there will be an additional sofa/daybed.
I would look at pictures of the rooms and then consider how much privacy all 4 adults would appreciate. If privacy is important, book two rooms. We always do this when traveling with extended family. For exampe, while rooms at the
Polynesian Resort have a lot of space, when traveling with more than two adults, we opt for two rooms. It also helps to have two bathrooms for getting ready in the morning!
If you don't think you'll be in your room except to sleep, privacy isn't an issue, and cost is most important then choose a resort that best fits your budget and share!
Let me know if I can help any further with this important decision.