packaging - definitely go with a styrofoam shipping package. using something like the kind of plastic that florists use, tightly wrap the sides of the cake 2 or 3 times and secure with tape. give 1 wrap of bubblewrap. line the bottom of the box with bubblewrap and place the cake in the box. fill up the remaining space with dry ice and bubble wrap so that the cake won't be moving around if the box gets jostled. don't forget to write "this side up" clearly before you post it.
decoration - i wouldn't expect any decoration on the side of the cake to arrive in any condition other than squashed. something on top may be ok. sourcream or whipped cream would probably be too delicate. try whipping some creamcheese with a little powdered sugar and some flavoring like vanilla, lemon juice or melted chocolate. it should be soft enough to pipe out, but firm enough to survive bouncing around a bit.
crust - not all cheesecake crusts are made with cookie crumbs. in fact, cookie crumb crusts aren't all that strong. here's a link to an alternative crust recipe: Cheesecake pastry
you can add cocoa powder if you want it to be chocolate
cheesecakes, with all that fat content, tend to freeze well, so you may want to consider freezing it before shipping.