That is my tact when answering questions from generic people who I dont know the expertise level, knowledge, anything about them. No offense to them, I was YOU once. But if you start with the idea of a 55-59 rear end, which just bolts right up, you can then later if you wish, change the gearset as Tim stated.
But if you do that, you have done the heavy lifting already, since you now have open driveline (upgradeable) putting you in the ballpark of your goal.
There is NO right answer. The minute you think there is, someone wants to put a positrac, T5, LS package in their truck. Just saying what I did. Im good to go.