Whilst there's no denying you can't avoid having to spend some time in line, you can still get plenty done without standing in line all day. At London last year (which was my first experience of Celebration) I was able to get wristbands for all the main panels without sleeping overnight. I arrived at the venue for 5:30 am to make sure I still got wristbands for the main rooms for Rogue One and the Mark Hamill panels on the Friday and the Carrie Fisher and the Future Films panels on the Sunday. I easily got a wristband for Anthony Daniels panel on the Saturday even with sleeping in a bit later and not arriving until just before 8 am. The advantage of the wristband system is that you know once you have your wristband you then have the time to enjoy everything else that is on offer before heading for the main panels much closer to their actual start times. There are lots of other smaller panels that don't require wristbands that you can just walk into which I found really enjoyable.
I didn't get any autographs and only purchased photo ops for Carrie Fisher and Mark Hamill, both of which I did on the Saturday. Whilst I did have to wait a bit in line for those ops I still got a lot done on the day aside from waiting in line for my photo ops.
If you're still on the fence about whether to come or not all I can say is that as soon as I got back from Celebration Europe last year I bought my 4 day pass for Orlando as I couldn't wait to experience another Celebration even if I had to cross the Atlantic to do it!!