Insanity, but good for them.
Frankly of late I've come to realize that frequent short trips are far more enjoyable than ultra-long trips.
Especially when there are kids to worry about.
But if I was their age (I am), without kids (I'm with), with time (I'm without), and spending money (I'm without), this sounds like something that would really be the experience of a lifetime.
Of course, they'll never be able to fly economy again...