Based upon the data, it doesn't seem that the theme park environment is conducive to significant virus spread even though there are many reasons that I would think it would be conducive. Between WDW, Universal and Sea World there must be over 100,000 CMs (or whatever Universal and Sea World call their employees). The last week before they all closed, there had to be a few hundred thousand visitors to all the parks (non Disney included). Many of those visitors in February especially were from New York due to their mid winter break. We know that the virus was spreading in New York in February.
Yet, given all that potential, neither Orange nor Osceola county had a significant outbreak. In both counties other than a few "spike" days of test result dumps, they don't really have a curve, they have an ant hill. Both counties have (and have had) low positive test rates. Contrasted with Broward and especially Miami-Dade, it is clear that something is very different and that the environment in those two counties is more conducive to spread than the Orlando area counties.
Whatever the reason, the data shows that there doesn't seem to have been significant spread due to tens of thousands of visitors and employees interacting in theme parks in central FL. I'm not saying there is no risk of spread at WDW or another theme park. I'm just saying that the risk seems pretty low given the available data.
I'm not sure why this is the case because everything about a theme park (and especially WDW) seems like it would be the perfect environment for the virus to spread like wildfire. There is packed transit, disgusting surfaces everywhere, standing in queues for hours in some cases in close proximity to other people.
It's not just the confirmed case curve and the testing that indicates the outbreak was far less severe than I would have expected around WDW. The syndromic metrics don't show nearly the spike that the southeast Florida counties show.