you can buy a tool, usally called a 'sneaky pete' for doing the job with the crank still in
usually contains a corkscrew type tool for pulling the old seal out and another for pulling it back through
All street engines should run PCV
otherwise you risk contaminating your oil with fuel,water,etc.
the only reason i can think of you might NOT be running a PCV is maybe a race engine that is torn down frequently and the oil changed every race