No, Celtiberia will be very hard to hold. But you had darn well better hold Rettlewood and Thysan. We worked hard enough to get ya'll into those places, if you go and lose'em even with Terran and D'Haran armies routinely supporting you, I'll be more than a little miffed. At least hold Rettlewood.
It's a game of luck. If monsters are tame, growth will be exponential. Celtiberia and Thysan will quickly grow, providing you with food surpluses, an income, and a source for troops. The food surplus can then be sold to D'Hara to get more gold. Which in turn can help you fight the rogues.
