Zigzag asked what distance would catch people's attention.
Just for comparison, HK has about 19,000 miles this year, fitted around a full time job. Pat Kenny (male AUK) twice did 30,000 miles with a full-time job and around 22,000 most years.
In my eyes, 40,000 annual miles would be admirable for a lady riding to set a world record. That total would allow riding a variety of events in mixed terrain, rather than having to stick to a maximum mileage hamster wheel. There wouldn't be much time or energy to do anything else though and a single bike wouldn't be enough. Equipment just wears out too quickly, particularly in bad weather.