I think the easiest survival map is either Dome or Arkaden
Arkaden is extremely easy to survive
You camp down under where the escalators are in burger town. You place a machine gun sentry in burger town on the right and a grenade sentry in the plant in the far left corner. Then you are able to camp into burger town with your friend which also makes it easier to revive friends. People can climb over the counter buts its really difficult, dogs on the other hand have no problem.