Tools and spares needed to repair a chain on the road I'm increasingly riding long-distance randonees/audaxes and I'm pretty confident I can fix most simple things which might go wrong with the bike. However, I've never done anything with a chain apart from clean it and would like to be prepared enough to be able to effect some kind of repair if it broke, even if I ended up single-speed.

I have an 11-speed Campagnolo Chorus chain. I'm considering getting this chain tool, but what spare pins or other kit would I need? I'd prefer not to carry a whole spare chain due to the weight and space.
Replacing your chain at regular intervals is by far the best maintenance money you can spend on a bike. Generally what goes wrong with a chain is a "stuck link" and 
the chain tool you have can fix that. Either by slightly tweaking the pin to loosen the link or by taking the link out altogether. If you do need to take a link or two out, avoid attempting to use the big/big gears. Generally there is no reason to carry a complete spare chain, only enough stuff to remove a link or two
and put the chain back together. 

Some chains require special replacement pins. Check with the manufacturer. Exactly what's required varies between 9,10,and 11 speed chains. 

For chains that have quick links, the quick links can break. Carry a spare quick link. You can use this to make repairs quick and simple. You can have more than one quick link in a chain w/o problems. 

For the new narrower chains, I am not confident about reseting existing pins using any chain tool that you can carry on a bike. This is why I only use chains that have a reusable quicklink. 

I'd think about switching to a chain like this in your case. Makes any on road repairs much simpler. However, I don't know of any 11 spd chain links that are 
reusable. 

I've done a bit more reading on 11 spd chains and I would definitely add a few spare used master links to your kit. KMC makes them and from what I read the old school method of pushing the pin back in just not safe with the very thin plates used to get chains narrow enough for 11 spd. KMC claims their quick links will work with any 11 speed chain.