well menus are hardcoded - what do you load ?
as for maps I just developed a map editor which serializes using kryo the map and can load it again.
Never that simple but yeah. short answer is write a parser or use serialization.
what exactly are you saving/loading ?
I wrote a simple framework for custom interface components. As a simple example... When creating a button I need to load the X/Y coordinates of the button along with three sprites for the default, clicked, and hovered states of the button. The same thing applies to all tiles, NPCs, etc... in the game. To make it really simple. Almost nothing is hard-coded with the way I have it set up. A few things will probably have to be hard-coded eventually, but everything is just "load-n-go" atm.
Your serialization idea sounds like a simple solution even though it would require a fair bit of extra work to setup at first. Thanks, I'll look into it.