Most of that depends on how your derailer mounts. If it is on a braze-on mount, you can't move it up to accomodate larger chainrings. In that case, you could probably file off the braze-on, or just ignore it, and get a clamp-on derailer.
If your derailer clamps on, then you can slide it up to make room for the larger chainrings.
On some bikes, the chainstays flare out quite a bit, and you should check to make sure that a larger chainring won't hit them. That is a very rare problem, though, and you should be fine.
If you can get around any of the issues I mentioned, then you could put pretty much any chainrings on that bike. I think that 48/38/28 or something like that is good for touring. It is higher than mountain gearing, but lower than road gearing. (Actually, I have a 48/36 double on my "road" bike, and that is plenty high. The big 53-tooth ring on most road bikes doesn't get used to its full potential unless riding very fast downhill.) You should probably stick with the mountain bike rear gearing for touring.