I understand that this is a huge pack, but...
I understand that this is a huge pack, but can I fit all of my clothes and gear(sleeping bag, etc.) as well as a four person tent into it?
I can't imagine a trip, short of a full-on arctic expedition, that you couldn't pack for in this pack. I mean, the thing is almost 110L! Unless you're talking about bringing one of those steel-framed Wally-World tents that packs down to the size of a Volkswagen (and maybe even then) you will be scraping the bottom of your drawers to find enough clothes to fill the Red Cloud. You may have to pay a hobo to hop in as well. It's that big.
Dave is correct. With the 110L version you shouldn't have any space issues. The 90L will probably work just fine as well.
As previously mentioned, this pack is HUGE. It definitely causes me to be a much lazier packer, as I can just throw everything I want helter skelter into the pack, and not worry about running out of room. I lead scouting treks in the summer, so this pack is great for all my gear for two weeks (tent, sleeping bag, thermarest), as well as around 15 liters of water and half the personal gear of the chubbiest kid in the group. If your back can handle it, the Red Cloud can pack it.