Ohh so so exciting hun.

The picnic idea sounds great, what if you checked at the auto shops or even the cheap shops for one of those little gazebo things, we picked some up from bunnings on special for like $20 and it would be perfect to have 1 or 2 in the car and pop up if it rains or even just for extra shade on the day?

Food: bbq meat, some salads, sandwiches, fairy bread (for the kids of course ), mini quiches.. think of things that if possible can be made the day before and travel well.

Invites i like the idea of designing your own, i did DD's and then took them to office works to be printed, or get someone to help you design them if your not comfortable doing it yourself.

Cake - i cheated i bought the one for Ava... it was gorgeous though.

Have fun hun it's exciting... do you have a theme for the party, butterflies, beach, flowers etc... work around that on the invite if you do... lol