I thought: I'm going to take my old notebook and install Linux that will only be used for writing only. What do you recommend installing for this purpose? I have intermediate knowledge of Linux, but I didn't want to spend a lot of time configuring it.
I had a similar need where I always wanted to be able to start writing at a moment's notice, ideally with a key-bind of some sort where I didn't have to wait for the editor splash screen and various indexing operations.
I have created a flow where a key-binded system command would invoke a script which did the following:
1. Create a new instance of a terminal in full-screen mode / maximised (key binding can allow you to open up a terminal instance with parameters to specify view options)
2. In the newly created instance, open up a command line editor (vim in my case).
^^ The above is a simple starting point, however, you could add extra steps like disabling the network interface for a set period in the script, adding templates to different key-binding invocations etc.
If you just want to turn your old laptop into a fancy word processor just have your .xinitrc only start the writing app and you will not have access to anything else.
I suppose for these methods you would also need to have the script temporarily set your xdg default browser to something which is not a browser if your writing app uses the browser for help files since that would allow you to open a browser.
Why not just turn off all the devices and get out the pen and paper?
Edit: Probably easier to just have the script turn off networking then playwith the xdg defaults.