Gotta say -- though I haven't played Wyvern Crown -- that I'm playing the NWN version of Against the Cult of the Reptile God and it is fantastic. Best NWN module I've played in quite some time.
Well believe it or not I write back and forth fairly frequently with the author Olgar ... his name is Rich Barker. You are right. It is a STUPENDOUS piece of work on his part. He'd love to hear you say so too. Vote for the mod on the ign site if you can.
I am not sure what Rich is at right now ... I THINK he is going to give UK1: Beyond the Crystal Cave a stab, but I know he is going to update N1 with the CEP 2.0 material, including giant leeches and centipedes (a staple beastie from 1eADnD after all) and what not.
Have you given JayAre's A1, A2 and A3 module adaptations a try? They are also "amaztonishing" (to quote DGNH - and if you know that reference I'll be very surprised) ... I have yet to give A3 a stab, Rich Barker only drew it to my attention today....