I've done Ironman 5 times. Try Pringles.
1. High Fat Content so they stick to your ribs
2. High Salt Content so they help prevent muscle cramps
3. Very easy to swallow (they don't take much chewing)
4. You can get small cans at most rest stops which fit into your special needs without being too cumbersome
Potatoes are an old Ultra-Runner standby, but I think it's a bit too heavy for Ironman. In addition, it takes slightly more work. Stick with things which are already packaged and keep your life simplified on race day.
Another good drink is Sustained Energy. You can mix 1200 calories in a large bottle and flavor it to your liking. I highly recommend this product to all my athletes doing Ironman. It's Maltodextrin based so it doesn't cause as much stomach distress as other products.
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