American Parkour

I can't today, but would you be able to tomorrow?  I split my finger open on this giant rock this morning and I want to give it some time to heal.  Also my brother's going back to college tomorrow and we're going to see Hitman tonight.  Oh, and no, I'm not in Team Blackmagic...  and I might go to the gym on sunday.  In the autumn months if it's nice out and I have the choice of training outside or going to the gym I usually go out just because if I don't I feel like I wasted one of the only days I have left before there's snow on the ground.

This would be awesome, and as for the spots...

Some of the best I've found in Downtown Naperville:
-Parking garage across the street from Chipotle
-Picnic area behind Chipotle
-library
-Apartment buildings/Doctor's office next to the burger king
-Rails at Naperville Central High School (you can practice everything here, vaults, precisions, cats, you name it and this is the spot.)
-The North Central High School Campus (haven't been there that much but it seems like there's possiblities)

If I think of any more I'll try to post them.

To give some background on myself, I'm 16 years old and I've been practicing parkour for about a year and a half.  About 4 months ago I started getting into free running more.  I started in a gym with what I thought would be the easiest move, a double leg (mostly due to the fact that I wasn't comfortable being completely upside down).  I got it to the point where I could do it outside, but only off my deck (about 1.5 feet).  As I practiced my double legs more and more  I got more confident with them.  For some odd reason they started turning into side flips and my form started getting really crappy.  As I practiced them more my landings got worse and my knees started getting sore.  That's when I knew I had to stop.
So now, a few months later, I want to start over.  I want to start from a clean slate and get the fundamentals down that I should get down first before I start anything else.  I'll be going to a local gym more which should help with some fears.  My question is, what should I get down first?  What are the most important things to learn when first starting?  And how should I practice these?  Thanks for the help.

Hey, nice to meet you.  I'm 15 almost 16 and live in Naperville.  I'll be a sophomore at naperville central this upcoming year.  Ive been practicing parkour for about a year now.  Me and a couple friends usually go out on the weekends and sometimes go to gyms.  It would be awesome if we could jam sometime.  As for spots downtown has some, specifically the parking garages which we tend to stay away from now due to a run in with some cops.  There's some good spots near naperville central.  We're always looking for new spots though.  What highschool do you go to?  And if you didn't know the chicago land area has it's own pk site - www.chicagoparkour.com

Yeah, that's about it.  I look forward to hopefully meeting you.