Cycling training - 220km in 4 weeks
I would say that you should definitely work more on long bike rides and less on strength training. You can always wimp out on the hills and put it in an easy gear.  If the max you have done is 70km, then you really need to work on the distance part of it.

Another important thing to train for is how to fuel yourself during the ride.  Most moderately fit people could probably do 70 km without worrying about how to properly hydrate and eat during the ride. But when you get up around 200 km, you really have to think about how to eat and drink in the correct amounts so that you don't "bonk" when you are out on the road.