Yes, the $10 fee is for the PDGA weekend membership. This is on top of the $40 entry fee. There will be tough competition since there are less divisions than other tournaments, but the players pack you get is worth more than $50.
This fee would be just for the tournament. The seasonal membership is ~ $40 or $50. If you are a new member and join in September or later this year, it will also be good for next year, but this is only for new members, not renewals. You would also get a disc and a magazine subscription with that. pdga.com for more info. Hope to see you on the island! Get in touch with Dave Slater soon or you may be SOL!
about ten minutes. You want the boat to Ward's island, then hand a right and follow the road for about 5 minutes. The course is just past the firehall. You can also take the centre island boat but it is a longer hike to the course. Do not get off the boat at Hanlan's Point or you face about a half hour walk to get to the course.
Info here:
http://www.toronto.ca/parks/island/summerschedule.htm