That's a good point, especially since the trip will fall right at the height of Free Food. The fireworks time slot at Cali might be a close contender.That would put you at an early September trip? In all honesty, you should be able to get any of those.
However, if I had to choose, I'd guess that Artist Point would actually be the hardest to get. It's still a 1 credit, but near signature, restaurant. The other two are two credits, so slightly less popular.