1. Tie a good piece of string to it, so when you pull it out, the string 'replaces' it. Usually works quite well. Carefully tie new wiring to string (actually tie string to wiring) and gently pull through. Get something strong and decent, not a rotten piece you found somewhere
2. I've seen this one done but not tried it myself. Get yourself an old throttle cable (just the inner) or perhaps a cycle brake cable, you know the ones. You can use this, sometimes this method is better if you have completely lost the wiring and have to start afresh as its obviously a bit more sturdy than a piece of string, but still flexible enough to get around.
3. Expect to be cursing a bit when doing this kind of job. There's no 'time' really as such, depends on luck really.