When I did mine on my F-150 I just took the fuel filter off with the little tool, gas came out, but it wasn't under much pressure if any. I did let it set for awhile before I did it. I figure that if you just turn the key on the fuel pump kicks on for awhile to reprime the system, so the fuel pressure must disapate as it sits. Remember if you do the schrader valve trick to clean the gas up on the engine, I have heard of people not doing that and torching their truck when they test drive it right after changing the fuel filter.
Here is the link to the owners manual:
https://www.fleet.ford.com/maintenance/owners_manuals/default.asp
If you don't have any leaks and haven't submerged the axle in water I wouldn't worry about the rear end fluid, it is synthetic and is supposed to be good for the lifetime of your truck. I would change it closer to 100k though.
Tranny should be serviced at 30k, I just drop the pan, change the filter and clean the magnet, and top it off. Some vehicles have a drain plug on the torque converter as well so you can drain almost all the fluid out. I don't really know what the ryme or reason is but sometimes you luck out, I don't know if the newer Rangers have this or not, I know mine doesn't. Just dropping the pan on my '85 gets about 3 qts out from the 10qt system. I wouldn't bother flushing it unless the fluid looks bad or shifts wierd.
PVC should have alot of life left in it yet at 16k. You can go ahead and check it but I doubt anything will be wrong with it.