50 pounds is going to hurt something. There is no getting around that. Take the inexpensive solution and leave about 20 pounds home.

I'll add one thing to everyone else's great advice.

Stop for a rest BEFORE your pack starts to hurt. This comes from an old book on another topic. With that much weight, you should only be walking about 2/3 of the time while on the trail. This means a 10 minute break after every 20 minutes. Find a cycle that works for you.

Once you've walked until your shoulders hurt, your comfortable day is over. With that much weight, be careful you don't throw out your back taking it off and putting it on so many times.