John: Melting on high in 1 minute intervals can burn the caramels in very powerful (1800+ watt) ovens. You may want to amend the directions to 30 second intervals, then 20 second intervals once things begin to melt.
One of the things I learned from working extensively with meltables (candies, chocolates, colored chocolate, yogurt trail mix coating, peanut melts, etc) is that things go from fine to burned in seconds.
Low and slow works best and is much safer. Less of a chance for superheating means a lower likelihood of burning little (or big!) fingers.
For the crunch without allergy problems, consider adding a layer of crushed pretzels. Want salty deliciousness? Crushed potato chips.
Also an excellent crunch? Chex cereal of your choice. Or frosted flakes.
Add a layer of white chocolate chips while the cookie bar bottom is still hot, or maybe buying some cookie frosting (the fudge swirl kind) and layer that on before the caramel.
A blondie or fudge brownie base are also awesome.
...why yes, I do a lot of baking and cookie making. Why do you ask? :-)