i replaced my master about 1 year and 1/2 ago and the slave about 4 weeks ago. they can be purchased seperately. i am still using the old line. never asked if you could by the line seperately. i bought the master at advance auto and the slave at Rockauto.com.
if you look at where the line comes into the back of either cylinder you will see a roll pin on one side. drive it out and pull the line out. there is a rubber washer in there be careful not to loose it. both of my cylinders came with a new one.
the slave was pretty easy because it came with a bleeder screw on it and bleeding was easy. the master did not have one. it was a little trickier. since ihad it off i filled it with fluid and reconnected it, lost a some of the fluid in the process had a fair amount of air left in it. i had to pump it alot to get it working and it took about 7 to 10 days for to get back to normal. it has been working fine for just over a year.
if you look at the line coming out of the master it loops down and then back up. it made sense to me that the loop down would not let any air go far into the line and it would just float back to the resevoir. apparently it did because i have had no issues since installing it.
at the time i did not know about replacing the system as a unit. when i went in and asked for a master they sold me one. the instructions that came with it were pretty vague and did not say anything about bleeding it unles it came with a bleeder screw which mine did not have. that leads me to believe you could get one with a bleeder. i dont know.
since you are replacing the whole line bleeding will be an issue. but it can be done. but you will have to remove the whole system. ther is a good write up on how to do it at
http://mopar1973man.com on the main page under 24 valve trucks.