Hi Keith (KB8VUL):
Good point regarding SkyLab. I seem to recall parts of it were strewn across the Pacific, with the heavy airlock assembly landing in Australia.
Deorbiting the ISS safely is going to be a challenge and it will be the largest man made structure ever to reenter. Controlling WHERE the many modules, frame, etc. will land will be difficult and I suspect that doing this well will require "deconstruction" of the ISS and staged deorbiting, as much as it is possible to do.
"Parking" the ISS in a higher orbit is just not practical to do. The very low ~254 mile altitude orbit would have to be much, much, much higher to avoid the far upper atmospheric drag that is primarily responsible for the orbital decay that eventually causes nearly all LEO objects to slow and fall back to Earth. There just is not enough fuel available to do this with the ISS, nor is the ISS designed to do this.
BTW - Earths upper atmosphere "expands" during periods of high solar activity - which we are now entering - increasing drag on all LEO objects and will tend to pull them (and the ISS) down faster. More station keeping fuel is needed by the ISS to mintain orbit and more junk simply falls to earth.
High orbit "parking" at EOL is usually done to geosynchronus satellites ~23,200 up using the last of their onboard fuel reserves to do so. At that altitude, atmospheric drag is negligible.
I wish the ISS COULD simply start "cleaning out the gutters" by using its manipulator arm, but many problems prevent this. A LOT of the space junk is at a different orbital altitude or in a different plane. Much is very small. And the velocity differential and mass/momentum of larger debris would make the ISS trying to catch it much like a baseball player trying to catch a bullet or cannonball with his glove.
Bottom line is that when the ISS is eventually de-orbited, it's going to be a major project - or a major "Hail Mary", if no nation puts in the effort needed to do it incrementally and safely. How, exactly to do this will be a learning experience, and that usually means one or two "ooops!" events.
Brian - K6BRN