I have just looked in the book "Thai Food" (by David Thompson).
Both are very similar. The main difference I can see is that there are souring agents in the red curry (fish sauce and shrimp paste). These are absent in the panaeng which has peanuts as a major ingredient in the paste (and nutmeg).
The panaeng is also usually made with beef which is simmered in count milk until tender.
I think @roux is generally right, curries are like mexican moles, they have lots of spices and are fairly complex. But I do think there are some short-cuts.
The most important components in a curry are sweetness, creaminess, heat, citrus, salt, and depth. I don't know if by simple you also mean you want to use common ingredients, or just 'few' ingredients. This is what I would use if I only had common ingredients:
Coconut milk, cayenne pepper, onion/garlic/ginger, lemon/lime juice, salt/pepper, sugar/honey. I'd also add basil/cilantro/jalapeno for green, tumeric/cumin for yellow, ketchup/tomato paste/chili powder for red.
If you have them, the traditional ingredients you're trying to replicate are lemongrass, lime-leaf, red or green chiles, and fish sauce (or soy sauce).
Best Answer
There is no Pad See Lew. Pad See Ew means to fry with soy sauce. In Thailand this menu is typically cook with flat rice noodle, fry with kale, egg and soy sauce.
I agree that Pad See Lew is a typo error. When I type into google in redirects me to Pad See Ew.