I've been to SSW 2005 with my Mom in a WC... while it is very crowded, I didin't find it any more of a challenge then other outings with my Mom... There are many people in wheel chairs as well as those power chairs. During SSW at the MGM studios, they have a rather large area set aside which is suppose to be for guests in Wheel Chairs, and up to 3 guest traveling with them. What I found last year were a lot of people who were not in wheel chairs, and were in fact very mobile. The only problem I have with that is those who are truly handicapped and in a wheelchair don't have the luxury of moving up and down, a little fact that seemed to be lost on the majority of people in this area that was set aside. One women told me that she got in becuase she was nice to the CM at the gate... so I guess that there are always a few who will use this to their advantage... a shame in my opinion, but I hope that this year is different... on a site I checked, they said they would be more strict with the rules this year... it remains to be seen.
If you are use to manuvering his chair around, I would say you should have no problems... but it does get very crowded.
one thing, if you are going to try and get autographs of the soap stars, we found this to be very difficult to do.... to get an autograph, you have to get a fast pass... people get online at 6am (and before) to be there when the park opens, then, from what I understand, it's a mad dash to get the pass.. it was impossible to do this with my Mom in the AM in the chair, so my Sister went out early to get in line... what we found out is that you can only get one FP per person, and that person has to be in the park.... we couldn't imagine doing this with the WC, so we weren't able to get any autographs...too bad for my Mom.... but we enjoyed everything else....