I agree that increased visits to Disney World and Las Vegas indicate an improving economy. People do not spend their hard-earned money on frivolous things like trips and gambling unless their bills are already paid and there is food on the table. When economic times are good, people have enough money to buy what they need, and then it is human nature to spend the rest on fun stuff as a reward.
I think it shows that people have more disposable income than they used to, or at least they feel more comfortable spending their savings now as opposed to before. People may not be earning more, but at least they feel comfortable in their jobs to not have as big as a buffer saved up.
While many Americans choose to go to places like Disney World and Las Vegas as a result of increased cashflow and purchasing power, numerous other factos also affect these choices, including a desire to escape from the stresses of a bad economy. Thus, these visits are not conclusively indicative of an improving national economy, and may be indicative of the exact opposite.
I do not think that an increase in visits to Disney World are an indicative of our economy improved. Families may have saved up or used their tax returns for a trip to Disney World. Disney prices may have also lowered. As for Las Vegas many people try to get out of poverty by playing the lottery or gambling.