route -n get default
It is not the same as GNU/Linux's route -n (or even ip route show) but is useful for checking the default route information. Also, you can check the route that packages will take to a particular host. E.g.
route -n get www.yahoo.com
The output would be similar to:
route to: 98.137.149.56 destination: default mask: 128.0.0.0 gateway: 5.5.0.1 interface: tun0 flags: <UP,GATEWAY,DONE,STATIC,PRCLONING> recvpipe sendpipe ssthresh rtt,msec rttvar hopcount mtu expire 0 0 0 0 0 0 1500 0
IMHO netstat -nr is what you need. Even MacOSX's Network utility app(*) uses the output of netstat to show routing information.