Quote Originally Posted by crazycanuck View Post
1-The longest ride i've done recently was approx a 100km mtn bike event (very hilly) a few months ago
Ok, you've ridden a 100k on your mtb in one day? How'd you do? Mtbiking is generally twice the work (due to rolling resistance, weight, less aero, etc., etc.) of road riding (assuming you are using a roadbike not the mtb).

Lessee, big maths coming . . . . 100k x 2 = 200k.

I think you can do this.