Did this repair almost two years ago...
Did all 4 hangers at once, since the three that didn't fail (at the time) didn't look too strong...
If you have all of the hangers off, that is a bonus, but not necessary. Get your grinder out and grind the rivits flush with the frame. get a 3lb mini sledge hammer and a steel rod that is about 18 inches long and tapered to a point on one end (basically a large punch) place the point in the center of the rivet and hold with one hand and whale on it with the three pound mini sledge. those rivits should pop right out of there. Just make sure they are ground flush with the frame or the hanger so that they can't mushroom out as you whale on them.
Front hangers are no different than the rear, but it is harder to get the angle grinder onto the rivits. You will have to at least loosen the gas tank and move it away from the frame rail to get the bolts in for the new hangers...but other than that, not much different than the rear.
Good luck!
Edit...
Just saw you don't have the torx bit to remove the bed.... ugh... go out and spend the 10 bucks and get a half inch drive T55 torx socket and remove the bed. your life will be soooo much easier. all it takes to remove the bed is the 6 torx bolts, three 8mm screws around the gas filler neck, and unhook the tail lights (connector is at the bumper on the driver side) two people can easily lift the bed off the frame without any lift. it will take you about 15 minutes to remove the bed, unless you have a bedliner then it will take you maybe 15 min more to fight with the bedliner. I actually spent more time removing my bedliner than I did removing the bed itself.
Here is a good article on removing the bed:
http://www.therangerstation.com/forums/showthread.php?t=145892
Replace the filler neck while you are in there... chances are if you have the original, it leaks

(40 bucks on fleabay)
Edit Edit...
shouldn't need a lift at all, just a jack to support the frame while the hanger is removed. I did mine without any power tools or torches, the biggest issue I had was getting the rubber bushings out of the spring eyes...
AJ