I've printed on both cardstock and a wide variety of photo papers of varying weights. If you want to print photos as greeting cards, cardstock will not do. It simply doesn't have the proper surface to show a photo properly. You want either proper photo paper, or, as a previous reply suggested, prepared greeting cards that are intended to show photos well. In addition to the other suggested, I use Stratmore cards in either glossy or matte.
Get one of those expensive canvas British bags that will make you look like Indiana Jones and get all your equipment soaked when it rains. You can look rich, roguish, and foolish all at the same time. If it were me, I would keep it in a pelican case or something like that. Just in case one of my $2 a day porters drops it or something.