Though Mississaugua is a 704,000 strong sprawling burb if you live in west Mississauga you can be out in the country fairly quickly.

Eglinton turns into Lower Base Line and you can take 5th line or 6th line north to Steeles, a little jog left on Steeles , back on 5th or 6th and you can ride for hours in the country. Or follow Lower Base further west...and explore the farmlands that surround Burlington, Milton, Carlisle.

On the weekend, I often drive about 30 minutes north, park the car and have a blast in the Halton Hills. Take Erin Mills Pkwy (turns into Mississauga Rd) north to Terra Cotta. There's a little school on your left, Creditview Public School. (King Rd and Missisauga Rd). Park at the school, assemble your bike and explore. Cheltenham, Belfountain, Alton, Glen Williams, Georgetown await you.

I've heard nothing but good things about Brampton Cycle Club. http://www.bramptoncyclingclub.com/ They have organized rides every weekend, some during the weekdays, time trials and all sorts of other fun.