Telnet access to moderately old UNIX boxes

I'm running a couple of AT&T SVR4 machines and am thinking of doing an SVR3. These are running on old Intel hardware, in text-only mode, etc. Unfortunately I'm really worried about opening these to the public net because they obviously have a ton of security holes. For instance, it's really hard to get a modern ssh running on them, so I have to use telnet. I have them set up on a private network with a modern linux machine on both the public and private networks that I can ssh into and telnet out of. It also acts as a mail relay for them. SVR4 is not that old, so I'm not sure how many might be interested in it, but if you really are, let me know, and I can set you up an account and tell you how to get in. The machine has a bunch of the old text mode software we used to use in those days: games, email clients, and very soon, USENET. Even a curses-based menu system. It's basically a rebuild of an old public access UNIX system I used to run. I'm also interested to know if anyone out there with old systems is interested in building a dark network for retro computing folks using UUCP over tcp. I have this perverse urge to get pathalias running again and build a little UUCP mapping project. Because my SVR4 box is on a private network, I'll need to bounce through the linux box. I'd like to implement a set of private USENET groups, and file transfer. I am also considering completely blowing off net access for these boxes and just using dialup. I was thinking of buying one of those MagicJack thingies that give you a local number and unlimited voip calling for $20 a year and setting up a modem on it. The downside is that most folks don't have modems any more. Ideas? Am I just nuts for even considering something like this? -Tom