Skipping is planned, but as I keep saying, the game wasn't meant to allow it so adding this feature takes time. You can use goomat by approaching its console as anything but a slime. And to use it afterwards, you have to be a slime. There are nearby notes explaining the lore about it, which should be enough for most players to figure this out on their own.
The second question is loaded and impossible to answer without context. Just keep exploring the map until you find the end.