C.S.
I would recommend doing it at home. That way if your son gets tired or overstimulated, he can retreat to his room, take a bath, have a nap, whatever. And the party can go on around him. I did a huge party (at least 30 people) with out of town relatives and lots of friends for my first son and he HATED it! He cried for over 4 hours. He was miserable - too many strangers, too many people passing him around and he hated, hated, hated the smash cake. I learned my lesson and had my second sons' party as very small, just my family, and grandparents. That's it! It was so pleasant and lasted from afternoon until very late in the evening. My baby was napping when everyone arrived, got up, ate dinner with us, played, got some presents, went for his bath, said good night to everyone, went to sleep and we were still celebrating! Much more fun for everyone. Oh, and I didn't do the smash cake the second time around either. Just gave him some bites on a baby spoon - he loved it! Good luck with your planning!