First, check out
HoJo's discussion of the entertainment rate dates.
If your dates are there, book the dates by calling hojo anaheim directly (NOT the 800 number) during pacific time business hours.
If they aren't there but you want to stay there no matter what, you can book using a different discount (like 15% off rack rates for being a disboard member or 20% off if you have or will have an AP). Keep checking the link above, as dates are added often, and you can switch the discount to the entertainment book discount.
If you are booked with the ent book discount, or if you end up with that discount, buy a book that will be good during your stay (the cards tend to expire Nov 1 of each year), and when you check in, be prepared to show it to them!
Buy whatever book makes sense for you. If there's one for your area and you want to get that book, do it. If you will visit another area of Canada and might use it there, buy that one. IF you'll visit a US place other than the Anaheim area, get that one! If all that makes sense is the Orange County, CA book, get that one (it's just that that one tends to be one of the higher-priced ones, without much else in the Anaheim area to use it on). We always by the one that's good for our area of WA, as the grocery store coupons cause us to break even or, like last year, come out ahead.
Hope that helps!