Since you live in ID, you're probably not to far from a Les Schwab tire dealer, I'd go to them and get their advice on your tire situation. They're a real honest company, I've bought tires from them for many years and they will treat you fairly. If you replace all four. you'll be trouble free for at least five years, probably longer. They only sell good tires so you won't be faced with cracking again, especially if you can cover the tires when parked for long periods of time during storage.