Basically, add a TON of 'keys' that have no key binded to them, specifically in a category named "assists". These fun things allow you to pretty much move and all without a mouse. Example would be having another 4 keys that act as a target zone. And ofc, you can move your vessel with the target, place towers, select towers or other entities, etc. Another thing, right click/move commands should be possible with a keybind, and other stuff. Last but not least, there may be some bugs when having too many keybinds taken (example would be with fie's wall taking a keybind that isn't 5 or 1-4, and that keybind being overriden by money bag) but I'm too lazy to report it :3
Overall I hope I can play TDS without a mouse (might help other people like me who only take their laptops with them around everywhere and don't always play at home)