um, we have done the 8:05 Crystal Palace breakfast many times and it has never, ever taken 1 to 1.5 hours. 40-45 minutes more like it. And a couple of times, we even saw the characters twice in that 40 minutes. If you have later breakfast reservations once the place starts filling up... like 8:45, 9 or 9:30 then yes, you may be there an hour or more to see all the characters. But those early reservations are ideal for eating, seeing characters & getting out by 9:00.
They do not FILL the restaurant at 8:05. They stagger the reservations and seatings so as not to overwhelm the capababilites of the wait-staff (they can't get juice for all of the tables in their area at exactly the same time...so right at opening, they fill maybe 1/5 of the restaurant.) The up-shot of this means in that first hour, the characters do not have to stop at every table because most of the tables are empty the first time they go 'round. Even when we leave at 8:45 or 8:50 the place is still not full.
You will probably get out of the restaurant before 9:00...and they will allow you to go to one of the inside-the-park rope-drop areas (they have rope-drops set up at the entrance to Fantasyland...you can walk through the castle, but they will hold you at the other end.) They also have a rope at Tomorrowland direction and Frontierland/Adventureland direction...so you cannot even get to those areas until the park officially opens.
So no riding rides. But you are close to the area you want to be once the park opens, so you will among the first in line at rides. And awesome opportunity to get castle pictures without a lot of people in the pictures...the park is not completely empty of course, because Crystal Palace and the Castle breakfast do draw a lot of people. But there will only be a few people in area going to & from.
If you're not staying on site, though, make sure you book the 8:05 breakfast on a day that does NOT have Extra Magic Hours for Disney hotel guests. Because the park will fill at 8:00 AM with Disney hotel guests, and by the time you get out of breakfast, even though it will still be before the 9:00 regular opening you will still find long lines at the rides because Disney hotel guests will have been in the park for an hour! Go on a day when the park opens at 9, and no early opening for Disney hotel guests.