I finally have some success!
My client network is 192.168.1.0
My tunnel is 192.168.4.0
My server network is 172.16.0.0
I put the following lines in the advanced configuration part of OpenVPN server:
push "route 172.16.0.0 255.255.255.0" ;
route add -net 192.168.4.0 gw 172.16.0.1
I was able to find one PC on the server (172) network and browse the files in Windows Explorer. I was not able to find another PC that I left on and made a shared folder on though. Maybe a Windows Firewall issue? The PC I can get to has Symantic Endpoint installed on it bu the one I can't get to is just whatever MS has.
Whatever the issue is there, it seems like since I could get to one PC any other issues are going to be configuration of the various PCs on the 172 network.
In Angry IP Scanner, the machine I could browse to shows up with a hostname. I think the other PC is in the list, but without a host name. I could also log into a NAS device. I can't see any of these things in Windows Explorer. It just shows the 168.0 network.
Assuming I can get the rest working, is it true that my Road Warrior clients will be good on any remote network as long as it's not 192.168.4.0?