dd-wrt router configuration assistance

i would like help to setup a dd-wrt router for various solutions such as vpn server, dual networks, dynamic dns, and possibly more; at this time, i need help with creating 2, separated networks; Network 1 - PRIVATE (my own lan) Network 2 - GUEST (visitors, family, friends, etc) PRIVATE on port/interface 1 GUEST on port/interface 4 want each to have their OWN Internet, but also then be secured, NOT communicate to one another (so private cannot ping/telnet/ssh/etc to guest, and reverse, guest cannot ping/telnet/ssh/etc to private) also, would like assistance setting up the router as a vpn server, so i can securely/safely remote in from the internet to my home network, to access resources internally over secured/encrypted connectivity