Hi!
The Superpowers RPG demo project might help, it has dialog boxes and 2D exploration. It's not quite what you're looking for but should be a good start to learn how to build your own.
(I'd love to have a native visual novel project type at some point too, so that it doesn't require any special coding, but I doubt I'll have the time to tackle it anytime soon so hopefully someone else in the community will take it up ^_^)