I haven't been back in more than a year. Returning 10/29-11/4. Would it be worth it to purchase the card during the trip then use it? Or just go directly with AP discount?
Depends. The TiW for APs is $150. The discount is 20%. If you calculate that using the 20% discount will save you more than the purchase cost of the card (it's good for 13 months), then go for it.
Here's the website. Check it out; not every restaurant accepts it and there are blackout holidays.
http://tablesinwonderland.com/