I have about 8 jars of peaches in light syrup I bought from Costco. I want to add these to a 5 gallon batch of Cider. I'm going to a peach cobbler flavored cider. I'm also planning on adding brown sugar. Should I prep the peaches in any way? Do I add these to secondary? What should I be looking out for? Am I crazy?
First off you are not crazy, adding fruit to alcoholic beverages is an age old process. You have a few options, you can add the peaches to the secondary, minus the syrup.
If the peaches are straight from a can they will have been pasteurized so you can add them straight in if you wish. You may want to freeze them first to break down cell walls and extract more flavour.
You could also add them to your apple juice, as a blended pulp and brew them up in the primary and the rack off to secondary or bottle.
The joy of home brewing is the chance to experiment and see what happens, it may be terrible but you may hit on a genius idea. Try a few batches and see what works. The most important thing is to have fun, and please report back :)