Not a pro... These are only ideas with no practical experience to back them:
If you blow the water out of the above ground pipes, they could go through the winter. I understand that a quicker solution is much better.
Can you see rust in a glass of water that you pull from an outside hose tap (which would normally bypass any filter)? If so, how long does it take to settle out. If it settles out in a minute, there are separators that might be useful. The Lycos Twist 2 Clean could also be something to consider, but it may be smaller than you need. See
http://www.twistiiclean.com/ for descriptions of several products.
There are ways to clean wells, which I know you have searched on. The one where you blow air from a 5HP or better compressor may not work due to the depth of the well. Actually I am thinking it would have more to do with the depth to water. I also don't know if the air lift pump methods work. There is a method to use a "bailer bucket" that brings sediment from the bottom of the well. It would be tedious, but it might work for you.
I am surprised that LLigetfa suggested a filter before the pressure switch. It seems to me that a filter with a pressure bypass would be OK. The device would be normally closed, and it would pass water once there was maybe a 20 PSI drop across the filter. This is often done in cars for oil. I don't have a pressure bypass to point you to. Another idea that I have is to put an additional pressure switch in place that would be before the new filter. This would be set to shut down if the pressure got to 80 PSI or more. It would be wired in series with the current pressure switch. You would add gauge with a tattletale before the filter. That remembers the highest pressure it has seen since reset. That could serve to give warning that you are getting close to needing a media change.
Suppose you had a filter bypassed by a CSV that is set to a very low pressure, such as 20 or 30 PSI. A CSV is like a bypass valve that opens at a particular settable pressure, but it is built to provide some flow all of the time. In its normal use, it keeps the pressure tank from reaching cutoff pressure for maybe a minute or so. If you did not find a normal pressure relieve valve to bypass the pre-switch filter, then maybe a CSV could at least send most of the flow through the filter except in clogged conditions.
How big is your current filter? If it is 2.5 x 10, I would replace it with a 4.5 x 20 Pentek Big Blue. If it is a 4.5x20, I would put in a backwashing filter with media such as sand, or perhaps other media that can do some needed treatment at the same time that it is doing mechanical filtering.
I see Lakos Sandmaster is intended for use
http://www.lakos.com/gwi-products/sandmaster-smp before the pressure switch. If your rust settles out, that might fit the need even though the intended use was to separate out sand. "These NSF certified residential separators can remove unwanted solids that can settle in 3 minutes or less, extending life of water treatment systems."
And finally an easier potential help. Run the water full blast out of the hose bibs for maybe 24 hours or more. If there is any chance that you would run out of water, you should have a pump protection device that shuts down the pump if you run out of water.
Wilder idea: Suppose you pumped from greater and greater depths. Then you raise your pump by 20 feet, and let the sediment accumulate for the next 20 years. I don't know how that would work out. Probably the most wild of these ideas.