All right, in order to start doing something cool I need a to navigate in. RougeBasin to the rescue! They have a really cool tutorial on a BSP dungeon (Binary Space Partitioning, simply put: a node tree where every node has two child nodes). Link here
First step: Create a child node of the entire area. Then randomly split it vertically or horisonatlly (offset the split by a random amount) and add the two inner segments as childnodes. Then repeat for each child node.
Second step: Take all the leaf nodes, shrink them a bit and move them around by some random amount.
Third step: Draw a corridor between every sibling node. Then move up to the parent node and draw a corridor between those siblings. This picture only has corridors on it's outmost leafs.
Fourth step (cheat): Turns out that connecting the parent nodes are a real hassle! In order to keep any kind of speed I did a cheat and drew corridors through the center of each sibling node. As long as I don't offset any room beyond the center coordinate the corridor will pass through a room.
This was fun, but getting step 4 up and running took way too much time. You don't want to lose too much momentum when dealing with hobby projects like these, and this is good enough for me to continue with the next exciting step!