If I don't type this up now, I'll probably forget more. (I'll probably forget something already..)
On the WinUAE side of things, I imagine just bsdsocket.library needs to be checked. Though, other stuff like JIT and a ton of memory, etc etc are probably advisable if not needed.
With AmigaDOS, you need telnetd.device in devs: (the one I'm using reports version 1.-1..) Pretty sure it was from the amitcp.lha archive elsewhere on the forum. There's a shareware version on Aminet, and that one isn't it.. I'll attach it to this message. You also (probably) need to mount the fifo-handler (38.4 is on Aminet, though isn't that just a part of AmigaDOS? Huh.. anyhoo...)
telnetd.device needs to be configured with the file AmiTCP:db/telnetd-device.conf with the line "x y pacerate 19200 255.255.255.255" (assuming you want to allow all (255.255.255.255) ips access...) x is the port (telnet is 23) and y is the number of connections. (I haven't tested past 3, but more might work..) pacerate is important for AmiExpress running on a fast WinUAE. It doesn't seem necessary on (some) real Amiga(s). (I know of a guy running AmiX on a real Amiga and doesn't need it..)
AmiExpress just needs node(x)/serial/internal_unit.def tooltypes to be: serial.device=telnetd.device serial.baud=19200 serial.unit=x (x being node0, serial.unit=0; node1 serial.unit=1 etc) node(x)/modem/modem.def tooltypes: modem.init=ATM0S0=0 modem.reset=ATZ modem.ring=RING modem.answer=ATA modem.offhook=ATH1M0 These are important because telnetd.device 'emulates' a modem with those Hayse commands.. And why pacerate is needed.. It sends a fast, unending string of 'RING <date>' over and over.. AmiExpress sends ATA because of the 'RING' etc.. Without pacerate, on a fast Amiga/WinUAE it goes so fast it clogs AmiExpress which just drops connection.. (my theory anyway).
Note: internal_unit.def and modem.def can actually be named anything. AmiExpress just finds whatever file is in node(x)/modem or /serial
For zmodem, I didn't do anything in AmiExpress just defaults, though only two Windows term programs would work, one was shareware, the other is mTelnet here:
http://ozone.eesc.com/ TeraTerm for Windows wouldn't work, perhaps because it doesn't support automatic zmodem. I'd then just connect to 192.168.1.2 (my Window's IP address) Considering that works, I don't see why an outside connection wouldn't..