There are so many ways you could go with this. There is no wrong way. I think I would theme the food to your wedding 25 years ago. You could re-create the menu you had then. You could have a menu that reflects where you went on your honeymoon. If you have moved a fair distance from then, you could have a menu that reflects where you lived when you married.

I don't think the orgaization of the party will be much different if you renew your vows. That will be a meaningful part for you, but it won't actually take much party time. You can do it by getting everyone's attention and having them gather around. If you are having a sit down meal you can do it once people are sitting before they eat. You can make rows of chairs with an aisle and such if that pleases you, but it really isn't necessary.