Thanks eerybody! My husband does know how I feel, and he pretty much feels the same way (he gets even more annoyed than me sometimes!), but he doesn't think we can ask them not to come. We did tell them that we were going to be doing the parks at a quick pace, and we don't stop for meals and snacks constantly, so they knew that going into it, but they are not independent AT ALL...they couldn't even find their way around the hotel by themselves, much less on Disney transportation.
I do believe that they want to visit with the kids (though DS couldn't really care less), so maybe I will be able to get DH to take them for a long visit during Christmas break this year instead of them coming along. I really appreciate the comments, suggestions, and commiserating!