One of the hardest parts of these sorts of emails is the fact you are trying to process them alone.
If they being processed as a group activity I think the experience would actually be quite good fun. Brainstorming, exploring new ideas, and having in depth conversations are often difficult for me if I try to process them purely over email. So perhaps the best reply would be, "Thanks for the interesting info, can we have lunch sometime soon to talk about this further?".