It's generally a bit of a bugger traelling during the holiday periods - but not impossible. Things tend to be either abnormally busy, or abnormally quiet. And, truthfully, it can be difficult to predict what will be what.
If you can change the time of your visit do. If you can't don't worry - you'll end up paying more for some things and less for others. But it should even itself out.
Personally I've found the May holiday to be far worse- I have less than fond memories of rolling up at the local bus station to find it a true seething mass of humanity. And the airport was no better - albeit I did manage to get the very last seat on a flight going in the right direction so it wasn't all bad.