GFNY Chile Pacing

Hi, my friends and I (none of us with competition experience and we will probably not be anywhere near the podium, just for fun but looking for a good time) will participate in a Gran Fondo in two weeks. It is supposed to be 140 km, but this is the official route (128 km):

We wonder what a good pacing strategy would be. We think it would be best to push on the climbs, rest on the descents and join a peloton that suits our pace on the flats. But I would like to know your opinions. Any other considerations to keep in mind?