In particular, I recommend getting a dedicated tinycore USB stick.
...case of editing files to get on the dialup network...
Heh. On windows, I used to use my ISP's network cable directly to my computer, so I could access the internet without relying on a modem. I tried to do this on TinyCore without the help of GUI programs and got completely lost, it seems that only a very experienced user can pppoe this way.