Go 14-48 and see what you think.
Adding a 15 to the mix will work without having to lengthen the chain, so you can test both setups.
I've done many trips on both setups and I'm still not exactly sure which I prefer. X has enough bottom end to manage either but you might have to turn the idle up just a tad, to prevent it from flaming out at too low rev's.
For cruising, I always compare small DS bikes to my KTM's; running the X with 15-48 is like having the 5th gear midway between the 6th of the KTM and the 5th of the X with 14-48. (if that makes sense..)
Don't think that you will be lugging the bike up steep climbs with 15-48; you will have to ride some stuff with more speed (which is good)
I don't mind having to rev the Honda 1000rpm's higher in order to cruise at the same speed, seeing as the KTM's used quite a lot of oil in comparison.So it seems to me that the X is much happier at doing long distance than the pumpkin bikes.

I get the idea that they were built to have the piss ridden out of them for 1000 miles at a time.
Just like they do in the Mexican peninsula