1. On what type of network, you are trying to configure DHCP. For Fenced network - DHCP will be diabled.
2. Ho are you trying to create routed network in wizard? If you have one org vdc network and it is already added to vApp, then option for org vdc network will be disabled. you can create vApp Network and then in connection drop down you can select org vdc net to make routed vapp network.
HTH
