Stronghold Kingdoms is an MMORTS (massive multilayer online real time strategy) and has no offline or single player functionality at all. Try the original titles Stronghold, Stronghold 2, or Stronghold 3 for a single player castle building experience.
I'm just worried about starting. Wouldn't you get totally creamed the instant you started? By some dude that's been building for years? Or are the castles not persistent? If they are: you're screwed because there's no way to "catch up" on someone who's castle and army has been refined forever. They would come and annihilate you. If the castles are not persistent: why work hard to build something - then just what? Declare victory and move on to the next one? The whole point of building a castle is to make it persistent and everlasting.
i've been playing since February and I haven't gotten attacked by these so called super veteran players. You can join houses/guilds to seek protection if you want. It plays like any MMO; you can do it alone or work with friends (or make friends by joining a house/guild). I actually joined a house/guild with some APB Reloaded buddies.
Don't believe the 1 star reviews. The tutorial is helpful and no the tutorial doesn't send you out and commit suicide. There is a learning curve. It's a casual game so don't be disappointed that it doesn't have World of Warcraft graphics. I guess, simplistic graphics is a good term. If you've played the Stronghold series but would rather go the way of MMO, then this is a good game. If you haven't played the Stronghold series but want to play a free casual MMO then this is the game for you. Hope this helps!