Brian
The 4000 is indeed an old Cisco router. But the basics of IOS have not changed much and it should be a good router to learn on.
I think the most likely issue is media type. The 4000 router Ethernet interface has a connector for a transciever for AUI connection and also an RJ45 for 10BaseT. Since you describe connecting via crossover you must be using the RJ45. I suggest that you make sure that you have configured media type for the interface that you are using as RJ45.
If that does not resolve your issue there could be other things as well. It would help if you would do show run (in privilege mode) and post the output so that we can see how it is configured and perhaps help to find the problem.
HTH
Rick
HTH
Rick