Check out Endless biking. I used them and Darren is super patience and real cool. They run tours from North Van to Whistler. I don't know much experience you have with drops and skinnies so it's hard to tell you what to do.
Whistler has two hostels and a campground.
I won't ride alone somewhere unfamiliar in B.C. Call me a sissy but I would stick to the park (The park's not really XC)or ther river runs through it if you're alone.They see alot of traffic so you shouldn't get stuck out there. Temps in June can be down to 8 c at night. Try making a friend on the lift then asking if they want to ride the valley sometime. I've followed my guide off something in the boneyard. This way you're at the correct speed. It's easier to make friends after you've done a head turner
You don't have to use a tour.You could grab Whistler mountain biking by Brain Finestone when you get there. Fanatlyk bike shop should have it. The book's pretty good for showing you around but sometimes it's got me in over my head. I would try the River or comfortably numb if you want a easier ride. C.N. is super long so I won't ride that the first time alone. If have a riding buddy, it's an XC adverture.
"XC" takes on new meaning here so be careful. Turning at a fork in the trail towards a sign with a diamond or double diamond will usually put you somewhere you might have wanted to look over first before riding. That's what's nice about a guide. They can get you comfortable with some trails then you can ride them alone for the rest of your stay. Guides aren't cheap so if you don't have the loot just look before you leap.
Fifty's right You should ride out to Lost Lake first. The trails are well marked and easy to navigate. Lost Lake reminds of XC trails where I'm from, Maryland USA.
Last thing.. Ride Fromme and/or Seymour. Those trail systems are in Vancouver. Fromme's kind of like XC. You climb a fire road then pick a trail to go down. Try Pipeline or Natural High first. You can stay a block from Fromme at Lynn valley B&B. Andrew's super cheap and his place is geared for Mtbr's. Don't pass up free awesome trails if you're going be in the area
here's links for stuff
http://endlessbiking.com/,
www.whistlercamping.com,
www.lynnvalleybedandbreakfast.com
Have a great trip!