With a simple dual link connection between two sites, and configuring two static and default routes, which route will be chosen or used by router-1 for known and unknown routes (with ip classless enabled):
[router-1]
E0: 10.10.10.1 255.255.255.0
S0: 192.168.1.1 255.255.255.252
S1: 192.168.1.5 255.255.255.252
ip route 20.20.20.0 255.255.255.0 192.168.1.2
ip route 20.20.20.0 255.255.255.0 192.168.1.6
ip route 0.0.0.0 0.0.0.0 192.168.1.2
ip route 0.0.0.0 0.0.0.0 192.168.1.6
[router-2]
E0: 20.20.20.1 255.255.255.0
S0: 192.168.1.2 255.255.255.252
S1: 192.168.1.6 255.255.255.252
ip route 10.10.10.0 255.255.255.0 192.168.1.1
ip route 10.10.10.0 255.255.255.0 192.168.1.5
Thank you for any input.