I am not a pro myself, but in my experience:
DHCP will create a complete routing table after acquiring a lease. So your default route to the internet will be available after configuring the network card with dhcp. You won't need to edit the routing table manualy. I think this is done after each new lease you get. Also, your dhcp client keeps a database with old leases which wil be tried at first, the dhcp.leases file. Practically this means it wil always try to get the old ip again. Unless the dhcp server blocks this, you will have an almost static IP.