I'm the membership manager for the club and will happily send you all the info you need if you send me an email as Sean suggests above. Just one thing to note is that we can only have guests come along on our Sunday rides for up to 3 occasions before becoming a member, this is for insurance purposes. As such, the Saturday laps and the Weekday rides are only available to club members.
On Sundays, sometimes the routes are posted in advance and sometimes not - it really does depend on who wants to lead a ride that day and how organised they are! Generally we suggest all new riders go on a Green ride (easiest pace), these can vary but there will always be one taken out that is around 60-65km. You won't need the route in advance as you'll be well taken care of by the ride leader(s) on the day.
As for crit racing, there is a good turnout by Islington at crits and it tends to be decided among participants as to what, if any, the strategy of the race will be. There isn't anything set by the club for this. For example, if an individual needs some points to go up a category then likely the other ICC club mates will help them achieve that goal, but other times it will just be a free for all.
If you have anything else you need to know then by all means drop any questions into an email to me and I'll be more than happy to help. Send me an email anyway and I can give you more information on the joining/trying us out process.