I contemplated a similar repair to my aging Ford F250 a few months ago and ended up taking my truck to my local [independent] garage for an estimate. Instead of detailing the work hours, the guy asked my if I had some spare time to waste and then commenced pulling out my entire old rusty, leaking, brake line. He then ran the replacement line off a "reel". He fed the new line through the undercarriage without requiring a single splice. I was back home in under 2 hours and the total bill for tearing out the old line and installing the new line was $104.00.
My frustration at home in my shop had to do with needing more elbow room to work and the need to see clearly up under my truck. Also, there was the question of making a couple of splices up under there without much wiggle room - if and when I bought a replacement line from some supplier. The local garage owner worked with ease with my truck on his "lift". Prior to this experience, I had no idea a brake line replacement could be done so easily.
Hope this helps. Good luck.