For mine we did a combination. We had the tables set up so that everyone was sitting at a designated spot (name cards) and then we had nibblies out for when people arrived, just stuff like chips, lollies and cookies. Then my husband was down stairs cooking kebabs on the BBQ (I had made kebabs that had steak, sausage and bacon alternating) and then when he was done we put them out with some salads as well as some mini quiches that were being kept warm in the oven - so it took a bit of prep work before but during the actual shower there was little to be done, just putting the food out on the tables. Then we cleared that away (not that there was much to clear, it was pretty much all gone), and we put out brownies, cupcakes and caramel tarts for desserts.
It sounds really structured but it worked on the day and didn't come across so structured, it still felt very much like a casual event. We asked people to arrive at midday, DH brought the kebabs up about 12:45 and then dessert about 2 I think?? We had the name cards out because I have a lot of friends from different areas (work, family, uni etc), I didn't want some to have to sit with strangers because other groups had spread out everywhere, it was my way of making sure everyone was comfortable where they were. It made it HEAPS easier for the games to. We played games pretty much the whole time until dessert came out.

It worked for us, I had a great day and there were a lot of positive comments. Hope it helps.