Routing - two routers on one subnet

Noted this from Rob Williams at Experts Exchange.

RobWill:
The configuration will work fine. The only issue is the remote VPN clients will connect to the VPN, but the replies to any of their LAN requests, will be sent to the default gateway, the Sonicwall, and therefore lost. To rectify this you can add a static route to the PC's/servers they connect to, or to the Sonicwall. The route will point traffic destined for the connecting client's subnet to the Linksys router's IP, rather than the default gateway. As an example on a server you would use
route -p add %20subnet%20> mask %20subnet mask%20> %20
eg:
route  -p  add  10.10.10.0  mask  255.255.255.0  192.168.0.254
There is a catch, you need to know the
subnet of the connecting VPN clients. Depending on the type of VPN you use, you might not know that, such as with the Linksys QuickVPN.