EDIT:
almost forgot, I do have a longer Ethernet cord kicking around, so I can try the single router trick (both computers into the router), for now, until I want to play around with networks some more.
It's great that there's multiple ways to accomplish one task though.
Just plugging them into the same router should be pretty plug-and-play.
My note above rambled a bit, thinking out loud, and probably made other approaches sound more complicated than they really are. It is more complicated than plugging into the same router. It really should work basically as you proposed it, if you really want to go that way. Might need a crossover cable and a distinct private subnet with static NIC IP configurations. I actually don't think you need ICS, so long as you are using RDP, although not 100% sure. I think the following approach should work though:
Prereqs:
300GL plugged into router and Internet access working.
Unused NICs in both 300GL and Intellistation.
Cables, duh, at least Ethernet, quite likely a crossover as well.
Depends on if your NICs are smart enough to sense & adapt to using a normal cable in a crossover situation.
1) Pick an RFC1918 compliant private subnet different from main router
Examples 192.168.99.0 mask or 10.1.1.0, both masks of 255.255.255.0
2) Assuming you pick 10.1.1.0 subnet, the assign static addresses to each
Example 10.1.1.2 for Intellistation and 10.1.1.3 for 300GL
3) Enable and configure linked NICs with above IP addresses and 255.255.255.0 mask.
I don't think the default gateway needs to be defined as traffic on the same subnet doesn't require routing. But if it is required, the 300GL should already be set so don't change it, and set the intellistation to the IP of the 300GL private address (10.1.1.3 in our example).
4) Connect unused NICs with normal Ethernet cable
5) Assure link lights show successful link
6) If success, move on, otherwise get crossover cable and try again.
If both normal Ethernet and crossover cables fail, one of the NICs may be bad.
7) At this point you really should be able to launch RDP on the 300GL from the Intellistation and access the Internet.
If it doesn't work, then would have to do some debugging which would basically be rechecking the steps above and possibly looking at some netstat output to check that processes are properly listening/connecting and that routing tables look right.
So the second approach is obviously not plug-and-play like the first but something you could do with some time to set it up and troubleshoot if needed. And you can always fall back to the simple method then continue when you have time.
