Is the drive mounted RO like on the car player.

No, I don't think so. I think it's RW all the time (someone correct me if I'm wrong).

And its kernel and software is significantly different from the car player, so no, you can't do all the same things with it that you can do with the car player. Dunno if the Telnetd you're trying to install will work or not.

I assume you've got a USB keyboard working on it by now? Once you've got that, to get files transferred onto it in the absence of a Telnet daemon, you could burn a CDRW with the files, then mount the CD-ROM drive at the shell prompt. I don't know the exact mount command, though.