Yeah, as far as the campaign is concerned, assume that it's fairly easy to get your hands on rations and forage for food and the like. You guys are adventurers and treasure-seekers, not survivalists. Keeping track of food and water is a minor aspect of the game that is annoying in the early levels and trivial as you gain more levels. The same goes for money spent on rooms at local inns (unless you're in a big city and plan on staying at a high-class hotel or something). Assume you've got a stash of party resources for paying for this sort of thing, rounding off transactions and taking the copper and silver pieces none of you guys really use anyway and saving them up.