I dunno about other folks on this forum, but your request seems to be a little 'left field' - not the usual sort of request for suggestions I've seen here, and I really wouldn't know where to start - creating a goblin lair or a vampire's castle or even an illithid cavern-complex is doable because we've seen those things or similar things before. How big and complex are you expecting each god's base to be? What sort of style? A castle in the clouds? A massive monastary-complex? A simple shrine?
Actually thinking a bit about it, the realms of evil gods reminds me of some of the dungeons and adventures involving demon lords (certainly a starting point for the evil gods). Queen of the Demonweb Pits involves tracking Lolth down to her Abyssal plane which is a convoluted network of pathways (if I remember). The City of Skulls was a Greyhawk adventure against Iuz the Old (a demigod), and involved infiltrating his capital city and attempting to rescue a VIP from his dungeons. Rappan Athuk was a massive dungeon with Orcus at the bottom of it all.
I think the best way to use the Workshop forums is to produce the work yourself, put it on these forums and ask others for their opinions. If they like it or feel they can contribute, you will get feedback.
I hope this helps.