From one standpoint, all the "mainstream" touring bikes are a lot alike -- Surly LHT, Novara Randonnee, Trek 520, Fuji Touring, etc. Enhanced tubing to reduce shimmy with a load, somewhat raised bars for comfort during long days in the saddle, wider tires to support a load, mounting points for racks and fenders are common. Most have stayed with 9-speed (although the Novara went up this year). You'll want to check the crank to make sure you get an adequate low gear (one target is 20 gear inches) in case you ever hit a steep climb while heavily loaded at the end of a long day; sometimes the makers will take a short-cut and put a road triple on "to match the component manufacturer's recommendation." IMHO, a 26 or 24 small crank is a good target.
One wrinkle is the the LHT has a somewhat longer top tube than the others for a given frame size. For many women, this will make it difficult to fit the bike -- many women have shorter torsos and longer legs than men of the same height. If at all possible, I suggest looking far and wide to find stocked bikes in early spring. Test ride a few -- at least 3-5 miles -- and see which one feels better to you. If you have to buy "blind," make sure you've got a great bike shop with a good fitter. You may have to go a size smaller than ideal, and make up the smaller frame with a different, non-stock stem. That's where the great shop will work with you; the young whipper-snapper racer wannabes will push you to the bike they want, and the race fit they like, which don't work for most (not all) tourists.