Just bury 250TB worth of SSD storage, along with a device that activates every year and copies from one 5TB block to the next. Any single SSD will only be in use for a year. If the drives can survive 49 years before their first use, it will work.
Storing the data in some ridiculous format is just going to discourage anyone from ever reading it. I'm sure the people of tomorrow have better things to do than OCR millions of sheets of paper just to see grandpa's porn collection.