This can go one of two ways. Really well, or really bad. Someone was bound to take the DayZ concept and implement it into a server just like the hunger games rsps.
Just a few ideas and my own opinion.
1. Use your own interfaces and perhaps some custom sprites. Using the runescape interfaces look kinda sloppy for something like this.
2. With your construction, you have to take into consideration what's the whole point in building bases in DayZ? To hide, to hide your gear, to protect what's in the base correct? You need to adapt your game to serve this function. As of right now you are most certainly not "hidden", or from my best guess because you'd be able to see the player in the base on the minimap. Noclipping through the walls would probably work too and someone who is competent enough would be able to do this regardless of obfuscation and things like that.
3. I understand this is a runescape base and it's not the arma II or DayZ engine, but on the actual game you can't walk through zombies, which makes it a hell of a lot harder if you get boxed in by them. On runescape and servers you can just walk through them.
I'm liking the idea though, if this was done right this could be really fun to play