One small thing I could do, and it might enable me to simply use the Linux command line utillity I already wrote, is try acp_commander. Then I could get telnet access all the time. That sounds cool.
But the questions about that method are these:
1) This doesn't modify the firmware, right?
2) Is it safe, the readme says it might "brick" the thing, but is the telnet command safe? I can have no chance of bricking the thing because I only have money for the one I bought, no money to buy replacements. That's why I don't even want to try flashing. Plus, it's simple to set up, it's just I need an automated method if possible so adding users and groups doesn't take all day.
Even if it worked, right now I'd not want to make what's simple complicated by making it a full-blown Linux server, powerful though I know it can be. For that, I want to use my old PC, but not relying on it's setup for simple file management.
But if acp_commander is basically 100% chance of not bricking the thing when I do a simple telnet enabling, and if it's trivial to make it come on all the time, and if it would accept my commands using a modified version of the same script to add users and groups, and if I did so, I could also rely on it showing up in the web-based utillity, then there's no reason to force going through the web utillity.
But if there's a 5% chance of bricking it or more, that's way too much and I'm simply looking then to go through the web-based utillity and automate that instead.