Getting Into Riding Shape
So what's the trick? I usually try to get as much time in the saddle over the off season as I can, but it never seems quite enough. Really, what works for me is jumping right in. Once the weather is good and the trails are dry I try to get out for 2 to 3 rides a week for a couple weeks. I don't hit it real hard, but I've found that a few consistant rides get my body to adjusted quite nicely. I notice significant improvement both in my rear end as well as my endurance after just a couple rides.
So don't be intimidated by your lack of riding shape. Just get out there and ride. You'll be surprised how fast your body adjusts.

Comments
Personaly i ride to work every day, what ever the weather. Then do two 10 mile and one 20 mile for 4 weeks. After then a 50-60 mile is acheavable. Then i am only a fun rider.