Your question about yardage for the camo fabric for a generous size twin. You also said this will be a one piece quilt. Then for top you will need at least twice the length plus a little extra as it will need piecing.
Fabric is probably 44" wide and a twin should be wider than that. So you might use the 44"x72" (or whatever length you need) and put a border around it to extend the width. I would do the same for the back but probably put a strip of fabric down the middle to extend the width.
Does this make any sense. Not sure it does to me....lol