I'm going to on vacation in the Sierras this summer. I have two riders--DS3 (nearly 3) and DD (8 mo) and I'm trying to decide between bringing my MBUD and my MBUS. My first inclination is to bring my MBUS and my ergo for use on trails/walks as the MBUD is just that much wider/heavier but DS3 does ride pretty much all the time (he's a runner). WWYD? I suppose another option is bringing two singles (yes, I have two MBUSs--I'm pathetic!) We will be on trails, and on roads and seldom indoors.

Would love your opinions!