As already said in this thread writing a game engine is a piss poor use of time. And you will not develop anything remotely close to a UDK single handedly because they have big teams comprised of the most talent programmers in the industry with years of experience and know how. But that is not to say UDK is even suited for your task.

What you really might want to focus on is an engine that runs on top of and existing game engine. The higher level part that represents your game logic and structure. Atleast this is my approach.

Unity3d is easy to use i think,if you know c# or javascript