I have thirty years of whitewater kayaking experience, and have done many multiday whitewater unsupported kayak trips, including a lot in the 1-2 week range. This August I did 10 days of kayaking on the Selway and Midddle Fork of the Salmon Rivers in Idaho. I posted pictures from those trips at
http://www.northwestkayakanglers.com/in ... ic=13913.0 and
http://www.northwestkayakanglers.com/in ... ic=14090.0 . I have the following general suggestions for camping out of a kayak:
1.
Pack light. Pack like a backpacker, or perhaps like a bicycle tourist. Don't pack like a rafter or a car camper. You don't need a huge pile of gear to kayak and camp safely and comfortably. In a whitewater kayak, it's easy to bring about 50% more gear than most people carry when backpacking. In a sea kayak or a fishing kayak, you can carry a whole lot more gear. Resist the temptation. Go light. One reason I prefer kayak trips to raft trips is that you have a lot less stuff to deal with.
2.
Try to keep the weight low and towards the middle of your kayak. Put heavy objects as low as you can and towards the middle of your kayak. Put light objects higher in your load and towards the ends of your kayak. In some kayaks, particularly sea kayaks, there is room for a lot of gear in front of your seat, under your knees. This is a good place for heavy gear, but you need to strap the dry bag down so it won't interfere with getting out of the kayak if you take a swim.
3.
Put everything in dry bags. Put all your gear in dry bags, unless you absolutely don't care if it gets wet and sandy. What size and shape of dry bags you use will depend on your kayak and the size and shape of the gear which you want to stow. You can tie a great big dry bag in the gear storage area behind the seat of a sit-on-top kayak, and you can drop a pretty big bag in the front hatch of a sit-on-top kayak. You'll need to use smaller dry bags to get your gear into a sea kayak or a whitewater kayak. And you'll need to use quite small dry bags to stuff gear through small round screw-top hatches. Don't rely on plastic bags to keep gear dry. Grains of sand or sharp objects will poke little holes in the plastic, and they'll leak. A plastic bag will survive longer if you put it inside a nylon stuff sack, but don't store gear in plastic bags unless you really don't care if it gets wet.
4.
Attach everything to your kayak. All gear which isn't inside a secure hatch should be attached to your kayak. Strap it down, clip it to something, tie it to something. Be cautious about relying on bungie cords to keep gear attached to your kayak. Assume that your kayak will get tipped over and separated from you and spend a couple of hours getting thrashed by waves and bounced off rocks before you recover it.
5.
Pack things you may need during the day where you can get at them easily. There are some items which you will want to use frequently during the day, such as water, sunscreen, a map, and food. Pack these items where you can get at them easily while you are in your kayak. There are some items which you may want during the day, such as extra clothing or hiking boots. Pack those items where you can get at them easily if you stop on shore. There are many items which you won't need all day, such as your camping equipment. Pack those things at the bottom of dry bags and in less-accessible areas of your kayak.
6.
Wear a dry suit. In reliably warm and dry conditions, you can wear light clothing while kayaking, you can pack a complete change of clothing and warmer clothing for use at night and in the morning in your dry bags, and you can reasonably hope to be able to dry off your kayaking clothing every evening. But in cool and wet conditions, there are huge advantages to wearing a dry suit while paddling, because you can wear the same clothing on and off the river. When you paddle away from camp in the morning you may be wearing two-thirds of the clothing you brought on the trip, and you'll stay warm and dry even if it rains all day. If it gets warmer, you can take off a layer. You can rely on keeping all your clothing dry during the trip, and you'll need to bring a lot less clothing, because you won't need to bring two complete sets of clothing in order to ensure that you will have dry clothing to wear around camp.
7.
Group gear. There are some items that your group will only need one of, such as a big first aid kit, a water filter, a rain tarp, etc. Figure out who is going to bring these items, and distribute them fairly among the members of the group.
8.
Hang your food at night. Bring a bag and a rope so you can hang your food from a tree at night to protect it from bears, ground squirrels, ring-tailed cats, mice, or whatever other pesky and hungry varmints are found in the area.
9.
A couple of useful items to bring. While I'm not trying to give general suggestions for camping, Here are a couple of items I like to bring on kayak trips: (a) a 10' x 12' tarp, for rain and sun protection. A tarp will allow you to camp in comfort even in quite inclement weather. (b) A "Crazy Creek" style of camping chair, which is way more comfortable than squatting on the ground of sitting on top of your kayak. (c) A water bag for use while cooking, so you don't need to keep getting up and walking down to the river for more water while cooking. If the river is muddy, you can use a water bag to carry water to camp from a clean side stream. (d) One or two trash compacter bags. They take up almost no room in your dry bags, you can put food in them or on them while cooking too keep it out of the sand and dirt, you can hang food in them at night, and you can put gear on them when packing and unpacking your kayak.
10.
Do a couple of overnight try-out trips. Before you head out on a week long trip, take a couple of overnight kayak trips, so you can figure out what you need to bring and how to pack it in your kayak. Just as importantly, you can figure out what you really don't need to bring.
11.
Make a gear list. A detailed gear list will make it way easier for you to pack for kayak trips, and greatly reduce the number of items you forget to bring on trips. Make a list of the gear that you bring on your first trip. After each trip, add to the list everything you wish you had brought on the trip, and take off the list everything you didn't use. A well-developed gear list is really helpful.
Multi-day kayak trips are really fun. Get out there and have a good time.
However, I have a couple of questions about your choice of kayak. I have a Revolution, but would not bring it on a river trip unless the river was reliably more than about three feet deep, and clear enough so I could see the bottom at that depth. It's way too easy to rip the fins right off the bottom of a Hobie kayak on a river. If you take a Mirage Drive kayak on a river trip, you better bring a compete set of replacement parts, and all the tools you would need to install them.
Because the Oasis is a tandem kayak, it has less gear storage space than Hobie's solo kayaks, because a greater percentage of the kayak is occupied by people. If you will be in it by yourself, you'll have a huge amount of space for gear. If you will be in it with a companion, there won't be much room for gear. You'll end up threading a lot of small stuff bags into those irritating little round hatches.