Hi,
since the bits are all paid for, and not through a dealer, there's no swapping.
Might as well use them, and replace stuff if and when it breaks. You might want a nicer saddle;
but you might as well try that one.

The cheap $25 racks you can get at any bike shop are fine. Most people buy these absurdly heavy and strong racks that weigh many times what my rack weighs. I have been using a Tubus Fly, weighs 12 ounces.

Panniers basically come in three sizes, small, medium, and I know the sink is in here somewhere.
You want a good size for a multi day trip, but you don't need anything massive. Most people
use panniers that are held on with bungee cords, I like some sort of locking mechanism.

This is what I have been using.
http://item.express.ebay.com/Sportin...mdZExpressItem

There are many other choices, look around and see what you like.

A couple other things I like are inline brake levers and...
http://www.offthefront.com/sports.ht...ing%20Products

There are a couple tricks to taping the Grip Shapes on, and the instructions
that come with them are useless, IMHO. If you get them, I'll get you started.

A bike computer is very handy when you are trying to figure out where you are.
GPS is even better, but $$$.... Basically any computer will do fine, just pick one that you like the looks of.