Is there an easy way for creating a small network without running the Windows Network Wizard? I'll be using a router and 2 PCs. Would simply adding all the computers to the same work group do the job?

Same workgroup, same IP address details...sure, if you can do it manually then you don't need to run the wizard. Make the router DHCP and then set the 2 PCs to Auto IP.

I'm not at the place where the network is being built so I'll have to wait to see how things go. I'll tell you what happens then.