Two router home network problem
Can you still connect to the Internet with the Linksys router? I suggest that you go ahead and reset the SMC router to clear up your previously configured settings. Then before reconnecting it to the linksys router, make sure that you can access its web interface via 192.168.1.1. Don't disable DHCP as your computer won't be able to obtain an IP address from it automatically. Do not change other settings. Next, disconnect the ethernet cable and check if you can access the router interface wirelessly. Once done, connect SMC's WAN port to Linksys' numbered port. Make sure SMC's WAN light is on, as well as the light for the port you used on the Linksys router. Check if you can get online.
With this configuration, the linksys router is now acting like a modem, and the SMC as your router. As long as you're online when wired to the linksys, you should also be able to access the net on the SMC once you physically connect them.