Murphy's Law "Anything that can go wrong, will go wrong". There are no bullet proof design in our lives, so is your tour camping trip. Many of us would just go with a spare tube, tire lever, a handheld pump and a multi-tool. In my experience from off-road motorbikes and biking, I soon realised what is really necessary to have a complete minimalist Bike Survival tools.
UPDATE FEB 2013
Kindly view my revamped Bike Survival Tools Kit
Cable Ties - they are really useful in many ways. I have used it once when my daughter crashed her bike and broke the brake lever mounting. I used 2 cable ties and secure them in place and we were able to complete our next 3 days bike camping trip.
Chain Lubricant - After a muddy or wet weather riding, it is good to have some oil on the chain for smoother riding.
One Cotton Glove - Dun call me sissy to use a glove. Wait till you have to handle a loose chain and grease all over your fingers and you have no place to wash it off.
Duct Tapes - These is another great asset to help in temporary repairs such torn panniers, broken lever, punctured tube.....
Speed Lever - If you do not want your friends waiting for you. This is the lever that can give you a quick tire fixed. To know more here is a link
Handheld Pump - Definitely must have. This is one great pump from Topeak Mini Morph
Multi-Tool - Another must have tool for all the fixes around the bike. I have here is a Topeak Alien DX
4" Adjustable Spanner - Another tool worth considering. If your pedal uses a 15mm wrench, the Stanley adjustable can be used as a pedal wrench. Found out the other brand Bancho could not open wide enough but the Stanley could. Pedal wrench is useful when you need to break the bike down for transport. Usually I do not over-tighten the pedal, just hand tight and with a knock on the spanner, it should be able to come loose.
This is another repair kit that many do not carry
Schrader Valve Tool - This little tool is useful on Schrader valve only. For bike tubes using Schrader valve, you need to unscrew the valve to let the air out of the tube. Most third world countries uses Schrader valve tubes so if you need to replace a tube, this will come in handy.
Schrader Valve Adaptor - This adaptor is useful on bikes with Presta Valves. I only use it when I am at a petrol kiosk to pump up air in my tires or worst if my handheld pump fails.
Rear Derailleur Hanger - I had experience twice bent Rear-D hanger. Once that is bent, you will have problem changing gear and your whole trip will be ruined. Even you try to bend it back it will never be in the correct position. You will need a special tool such as Park Tools Derailleur Adjustment Gauge and nobody carries such tool on a trip. I would rather buy a spare Rear-D hanger than an expensive tools.
All the tools fit in the Topeak Aero Wedge Pack Medium except the handheld pump. This pack is not waterproof so after a wet weather ride, it is best to remove all item and let it dry. The whole tool bags weighs around 700g. Alone the Aero Wedge Pack weighs 140g and most of the weight is on the multi-tool, I might replace the Alien DX for Hexus and have all the tools stored in a small bag to reduce the weight.
This is a very useful item, Loctite 243. If you are going for long distance travel or off-road and to prevent loosing a bolt, use Loctite 243. A tiny drop on the thread will keep the bolt in place. It also helps to prvent rust on the thread. This big bottle 50ml can last for years so if you want to get one, there is a small 10ml bottle. Small enough to pack with your tools. Not recommended to use other Loctite like 263, you will have problem removing the bolts.