If you can find a book on planning weddings, not just etiquette, that would probably serve the same purpose as it will likely talk about etiquette, but that will not be the whole focus.
In my opinion, ring or not, if the wedding is not for several years, there really is no engagement. What is the point of getting engaged now and married years later? Why not get married in a reasonable amount of time (a few months to at most a year)? or delaying the engagement until they have selected a date that is within a reasonable amount of time.
I like the idea of a recipe box with a collection of favourite recipes, especially if you have any family favourites. I suppose you can consider that you are building the bride's trouseau and helping to fill her hope chest.