The DOT 5 (silicone brake fluid) is the culprit to the rusting lines. Since silicone fluid does not obsorb water/moisture out of the system, the moisture will pool up in the low spots of the system, especially the calipers or wheel cylinders, which is bad because the boiling point of water is so low, therefore leading to brake fade under heavy braking. The military uses it because the fluid itself is more stable under extreme temperatures than any other fluid at the time. But now a better alternative is DOT 5.1 is available which is a glycol bases fluid which will absorb moisture thoughout the system and has an extemely high boiling point.
The only way to stop the rusting is get the silicone fluid out, since the brake systems are vented systems, higher humidity areas will tend to suffer from corroded lines more often with silicone fluid.
DOT 5.0 (silicone) is not compatable with DOT 3,4 or 5.1, so a complete system flush is needed to swap. Well worth the time though.
As for the M/C bleeding, its not hard if you start at the M/C and work your way out. Definetlly need two people though to make it easier, although you can bleed the M/C by yourself if you grab the peddle from underneath and then bleed the fitting.