Yep... know the problem, most people today only have experience of old Explorers, which have been well used and abused, so when they say 'Oh they're all like that' it doesn't help at all!
I'm sure you know all this, but It does help to remember that the speed limit for these vehicles at the time they where built was 20 mph, try driving below that speed for a bit, you will be amazed how (relatively) refined it all is.
Then think that they wouldn't have gone too far without a good load on tow which calms down the manic rattles, and you get the idea that you are most likely driving it too fast....having said that I tend to do the same speed you do, and after years of tinkering I can now hold a conversation..:shocked:
Achilles heels, rear prop, rear hubs loosening and rubber couplings, if your prop is not 'as new' in all respects think about getting a new one, owners who have done this say that with modern seals they don't loose all the lube every 100 yards...always a bonus. When greasing your (old) prop UJs make sure grease emits from all four journals every time, grease it every time you move it!
Can't remember if you have rubber couplings but if so wrap them round with wire a few times to hold the rubbers in place if they come loose, and keep an eye on them every time you go out..
Rear drums, check regularly they haven't moved, paint lines across ends of nuts as a guide, after a while you will be confident they are tight and can relax.
Other than that make sure the noises aren't coming from all the various rods and linkages rattling about under the floor, cab panels buzzing against the frame, dog growling, passengers screaming etc. all basic stuff really