You are very welcome. Making fertile soil from dead dirt is my main reason for gardening: the flowers and food are less interesting to me.
As you can see, it's a major fetish!
>> I am a little doubtful that she is such a dedicated gardener that she would go through all that
Well, the low-effort path would be to drop a lot of compost-makin's on top of the areas where she wants to grow things. Sheet composting.
Like make a shallow compost heap over the largest area she has enough raw material to cover. Keep adding to the layer ever time she has more leaves, lawn clippings, newspaper, coffee grounds or fruit-stand-rejects.
Then wait a year or two.
Then deeply till in more organic matter and/or grit.
(double digging or a chisel plow or DEEP roto-tilling)
Then add more compost and mulch every year. At least one inch of compost and 2 inches of mulch.
OK, I guess that IS a lot of work too!
The lowest-effort approach would be to triple the amount of compost and mulch she uses now. But how long would that take to overcome hardpan, without some major breaking or deep cutting? Double-digging is probably not an option, and I doubt she has a chisel plow in her back pocket either.
Making raised beds, and buying soil might be the only low-effort solution to hardpan.
If I were her, I would look for someone willing to dig deeply in return for vegetables or cooked meals.
