2005 Ford Escape XLT making a LOT of noise when turning or going up/down hills... what gives???

It's hard to say from just your general description, but bushings are the first thing that comes to mind. The Escape has a lot of components in the rear suspension compared to solid axle vehicles, so there are a lot of places to potentially make noise. With 90k miles, it is reasonable to expect bushing wear, especially depending on the environmental conditions. If you don't notice any weird handling characteristics on accelleration/decelleration (suggesting a broken bolt or control arm), I doubt you have to worry about the "damn back axle" breaking off, but I would have it looked at by a competent shop soon.

Check the shock towers in the rear to see if they are rusted away

CV Joints may be causing the noise check see if the boots on the cv joint(constant velocity) are not torn or damaged may be leaking grease. no grease you get the noise. these axles are not expensive best left to good mechanic.

Maybe it's not what you have, but my 2005 XLT had a creaking noise in the back, on just every obstacle that caused the frame to flex, like when going out of an entrance. I found that pushing the liftback sideways, from out of the car, recreated the noise at will. Putting electrical tape around the pin where the liftback locks, eliminated the problem.