Avoiding the GayDays parks for those four days was our original plan, because of the crowds. In order to work in an E-ride night at MK, it was more convenient for us to visit the Disney MGM Studios on the GayDays day for that. Many of the gay people who attend the MK Gay Day on Saturday don't visit the other parks at all, and many people avoid the GayDays parks on those days, so it seemed that the number of people avoiding the park because it was the GayDays park of the day was at least as large as the number of gays attending. We didn't notice any increase in crowds at all.
One thing we did notice that we didn't really expect, was the number of gays who left the MK after the meetings and spent the afternoon and evening at Epcot. I am assuming that they went for the big event, and then said something to the effect of "I'm not waiting 2 hours to ride ANY ride! Let's go to Epcot!". Anyway, they were much more noticeable at Epcot on Saturday, than at MGM on Friday, because they were still wearing their shirts (red or decorated or sloganed or all of the above). There were also many groups, where it was mostly couples on other days.
We saw a lot of same sex couples and some gay groups during the week, but no inappropriate dress or behavior.
When we go to Disney, it is as soon as school gets out for the summer. If that happens to be the same week as GayDays (and it usually is,) then that's when we are going. After this year, I won't even bother trying to avoid the GayDays park, except for the MK on Saturday.
On a side note, on one of the other forums, someone told me that in recent years that Disney resort guests had been warned of the large crowds expected at the MK on Saturday and had been offered early entry at parks other than the scheduled one on that day. That was not the case this year. We were at the Yacht Club, and there was no mention of any kind of the expected crowds at the MK, and no extra early entry offered.