I definitely would recommend printing on card stock. You need a heavier weight paper since they will be writing and stamping the passport.
As far as printing and assembly...it depends on which passport you are making. Are you making one of Natalie's or the one that you print and fold like a real passport?
If it is one of Natalies, treat it like an autograph book. There are three ways that you can print and bind:
1. You could print on cardstock and add extra white to the top or side so that you can have it spiral bound at a print shop.
2. You can upload the pictures to a company like snapfish,
walmart photo, etc. and have it made into a flip book or photo album.
3. You could print on cardstock and slide into the pockets of a photograph album.
If it is the one that you fold like a real passport...it is set up ready to be printed. Then you print, trim and fold.