This should be a good discussion, I'm surprised nobody has bitten yet.
One thing I like to replicate as closely as possible is food while in the field. Experiencing the life of a soldier of the period by using all five senses makes for a more immersive experience for the reenactor. The public is often fascinated by a meal I might be cooking in my English mess tin, or completely disgusted at the tin of bully beef that I might be snacking on. Cooking also gives you a good activity to fill your time at Living History events. I like to have something to do, so that I am not standing around awkwardly doing nothing when not actually speaking with someone.
I have collected various recipes over the years for hard tack, ships biscuit, or other bread items that were issued, and I try to replicate the original packaging for these as well. Canned goods are easy to replicate using a modern equivalent. I remove the modern labels and replace with period labels I have collected and turned into .Pdf images for easy printing. If anyone is looking for Bully beef labels or any other labels, let me know. I have a pretty substantial collection of food labels for canned goods spanning the late 1800's to 1940's.
This is an interesting blog I have been following, which gives some pretty good insight and cooking ideas for the usage of the humble mess tin:http://joyoffieldrations.blogspot.com/