I've done a whole-sale replacement of lines twice now. the first time it was with the pre-flared straight lengths from the autoparts stores, the second time it was with a roll of DIY tube and a flaring tool. both methods were fairly easy to do. you don't have to perfectly follow the factory path, just make sure that nothing will snag on them and the lines are secured. I highly recommend the nickle/copper line that lasts waaaay longer than regular steel. oh, and if you flare them yourself, a quality flaring tool is key. the cheap ones suck.
now's the time to contemplate eliminating the rear prop valve and upgrading to the WJ dual booster.