OK, I'm convinced and ready to buy Ashes. But I'm not certain of the best way to do this. Please correct anything I've got wrong here...
It looks like I can pre-order Escalation for $30, and get the full game with the Escalation DLC. The previous DLCs will add on properly if I buy them.
I have a Steam account but sort of hoped there might be an independent alternative. When I look at the Escalation pre-order in the Store here, it can apparently be bought via Steam (where FYI it doesn't appear in the Ashes list of bundles so many will miss it) or via Stardock. The tag line says "Steam is required to play this game, unless purchased from GOG.com". How does a Stardock purchase makes any sense, if it has to be played via Steam? And, is GOG an option for Escalation, or only for the original game?
Related question: My only interest is in single-player. Only the Gauntlet and Overlord DLC even mention SP. Do the others (Epic, Oblivion, Turtle Wars) have any SP content? Can the multiplayer maps be played as SP against the computer?