Hi Dawn,
It would be great to have a crystal Mickey Mouse that tells you where the crowds will be but I have yet to find one. I like to use
www.touringplans.com when planning our Disney trips. Typically their suggestions are pretty accurate in regards to expected crowds levels. I have found personally, that the general day of the week guide, ie the crowds are smaller on Tuesdays at Magic Kingdom, is an average and does not take into account specific things like special events at a particular park or holidays. That is why the actual date calendar that breaks each park down into Best and Worst Park to visit on a specific calendar date sometimes contradicts the general day of the week guide.
Now I have found that if there are no special events or holidays occurring, that the general calendar tends to be quite helpful when planning our trip. I look at the date guide first, then the general day of the week recommendation. I also consider Extra Magic Hours and where I am able to get my desired dining reservations when making my final plans. If there is a specific attraction, special event or restaraunt we want to enjoy, and it goes against the touring recommendations, we continue on with our plans and hope for the best. While the guide is a great planning tool, I do not use it to dictate our plans as it is just an estimated guess and can be incorrect. If you have selected the park hopper option, the great thing is, if the crowds increase where you are at, you can hop on over to another park.