how hard to replace front brake lines??

Front brakes are basically shot. So are the rear. But I'm gonna concentrate on my fronts first, then tackle the rear drums. Is it relatively easy to just replace the brake lines and refill the fluid??

Yes it's easy, just follow a manual and keep everything clean. Might as well replace the calipers while you're at it. No sense putting new stuff between old stuff, and "new" rebuilts are cheap.