Most folks who go to lower gears on a Trek 520 are carrying loaded panniers. I would think your gears would be fine for non-loaded riding. You will see many riders on MS150 type tours riding bikes with double chainrings; some will envy your small ring, some will look at it with disdain. A 22 ring will give a lower gear than the 30, but you also end up with a high gear that is not as high. I'd say ride what you have until you are certain you have a reason to change it.

You can find a great deal of biking info on the net apart from asking questions on borads or buying a book. For general touring info check out Ken Kifer's site. For mecahnical things look at Sheldon Brown's site. I don't have URLs handy, but do a search for their names and you'll strike paydirt.

But few people mind answering newbie questions. We have all been there, it is just that for some of us it was so long ago we have forgotten. Ask away!