As stated there's lots to consider, however since your preparing for usage, I'll assume you're studied up and answer your question:
V8 will provide many of the salts that it will leech from your system to which I'd also recommend stocking up on Gatorade for electrolytes, and purchasing some Taurine (fluid balance) and Pyruvate (eye & sight protector; damage to his area is a notable DNP side effect).
To replenish antioxidants in an effective and affordable manner I'd highly recommend using supplements and not food. Such a strategy will permit you to greatly enhance their accurately measured amounts and thus protection. This or a product like it, there’s one at GNC would be a superb choice:
http://www.purityproducts.com/product.asp?sku=380
M.