If the drive sprocket turns, you should be able to get it back on by doing the same way you'd put a bike chain back on, ie:, hook it into the teeth and turn the sprocket while running the track back over the idler... As for saving the weathering, can't help ya there... Track is flexible, weathering isn't...
If you got everything glued, well... That's another story.. The problem with stretching it to get it on is that you can't "un-stretch" it after it's back on...
Best bet would be to be to sew it back together in an inconspicuous place and apply a little "mud" to camouflage the break...