i am thinking and typing here so please bear with me. The main concern i see brought up is the fact that some places have few players and if those players split into wanting core and not wanting core then there is an impasse. Personally i think that 90% of the time this happens there will be people gracious enough to go along with whatever and play a pregen or make a char.
Here is how i plan on handling this in my region.
background: I drive 35 minutes to gm a group of 4-9 players. Sometimes we have two tables sometimes only one. our game nights are Thursday 5:30-9:30+
I have announced that every third Thursday of the month is CORE thursday. For the new guys and the old timers i am going to run season 0 - 1 and start from the very beginning. This will also be the night that i spring for a couple of hot and ready pizzas and a couple two liters of soda. My group is (so far) excited about this and asking what i want them to bring for treat night or if they can toss in a couple bucks for the pizza. I am excited to see how it goes. i will let ya know
EDIT: for the new guy that drops in on CORE Thursday, grab a pregen grab a slice and i will talk to you after game about the Regular PFS nights :)
EDIT 2: don't feel like playing CORE? then we will catch ya on the other three nights! :)