There is a huge range in what folks choose to take, so there is no "one size fits all" answer.

I'd forget the 4500 cubic inch backpack. That is way more than I would want to put on top of the rear rack.

Unless you are willing to go really light, I would recommend getting some panniers. If money is tight (or maybe even if it isn't) Nashbar or Performance waterproofs are inexpensive and work OK.

If you are willing to pack pretty light, you could go with smallish panniers on the front and your tent on the rear rack. I did that on my last trip and it worked very well for a base gear weight of 22 pounds (excluding food, water, and fuel).

If you are carry a moderate load (30-40 pounds) rear only panniers is probably OK.

If carrying a heavy load (>40 pounds) 4 panniers are probably preferred.

If going really light (<20 pounds) you can do well with a large saddle bag (search for Nun's posts) or sil-nylon stuff sacks strapped on the rear rack.

I'd also use a handlebar bag with any of those options.

I am not a trailer fan so I'll let others comment on them.

Also if interesed in going very light check out my article on the crazy guy site.