The F&WF is great. But the food at the booths are more like samplings, not full meals. And they range from $3 to up to $5 or $6. It could get pretty pricey just eating at the food booths for the festival. It's not gonna fill you up just the food at the festival, at least it doesn't me.
Stuff is going on all week. They are busier on the weekends with the crowds.
I remember seeing "Carmal Ginger Ice Cream" at the Japan pavillian at the festival. I was over at Epcot the other week and the tea place at Japan has the same ice cream for sale all the time. I had no idea. Some of the items sold at the countries that are permanent countries there, usually bring out samplings from their menus. Canada had their "Canadian Bacon Chedder Cheese Soup" at the festival, which I got, because I love that soup. It's part of the menu at Le Celliar Steakhouse if you can get a seat, they are booked 6 months in advance. Hard to get a table there. But my sampling at the festival was probably about 4 spoonfulls and it was like $4 for that little bity cup. So you could rack up quite a big bill just eating at the food booths.
Reservations are definately the way to go before you come. If you have your trip booked and are on the dining plan you can book reservations for dining 180 days in advance. When I didn't live in Orlando and was coming to Disney I always booked them in advance. Now that I live here, I don't really need to book a room over there, so I don't have the dining plan. But I still can book a table service reservation over there even though I'm not staying there or on a dining plan, kinda nice. I usually eat at O'hana's at the Polynesian Resort, excellet food, my pick for the best table service in the entire complex. And my friend Ed is a server there. Actually his picture is on the WDW website for O'hana, he's the tall guy. He's worked at Disney for around 15 years. He's an excellent server.