They don't exactly stop seating for dining packages, but at a certain point they will open up seating to the standby line. I think 30-45 minutes is enough time if you don't care where you sit & you just want to make sure you get in before they start loading the standby line. Online you'll see people saying 45-60 minutes early for NPH. He is probably the most popular narrator so don't panic if you stroll by 3 hours before showtime & see a huge line. I think they start loading the theatre with the standby line around 15 minutes before showtime (but someone correct me if that's wrong) so be there before that. I think they also tell you a time to arrive when you have dinner/whatever meal you're doing, but I can't remember. The dining package guarantees you a spot so don't be late, but it's not necessary to be super early just to get your spot. Now, if you care about being in front, I'm sure there will be people in the CP dining package line 2+ hours early. I won't be one of them, haha, but people absolutely do it.