Radcliffe last competed in the London Marathon on April 17, 2005, winning her third title in the capital in 2hr 17min 42sec -which was and remains the third fastest women's time ever. Second fastest is Radcliffe's 2002 Chicago win in 2:17.18. The world record of 2:15.25, set at the London Marathon a year later, also stands to her.
No other woman has got within three minutes of Radcliffe's record - the fourth fastest performance ever is that of Kenya's Mary Keitany, one of the favourites for this year's race, who clocked 2:18.37 in winning the London Marathon in 2012.
And so the 41-year-old mother-of-two - and it's also hard to believe that description now fits the game teenager I saw chase home Olympic champion Derartu Tulu in her first senior race, the 1993 Durham cross country - is homing in on what will be an almighty homecoming.
Now we are looking at a ludicrously fit woman on the brink of middle age who is also negotiating unknown mental territory. Having been initially grateful just to be able to run following the serious foot injury - one of an escalating sequence of physical breakdowns in a body which has been driven to its limits for more than 20 years - Radcliffe has been able to train regularly and seriously in the course of the last year.
But, by her own admission, she goes forwards to what she wants to be her final flourish uncertain of whether the mechanics will let her down again.
For years, Radcliffe has advocated the wisdom of "listening to your body". What is hers saying now, one wonders? "Maybe Paula. But don't push it, yeah?"
When, in May last year, Radcliffe first floated the idea of a final 26.2 miles run-out in either London or New York, she reflected: "I'm not thinking I can get back and run 2hr 15min, but if I could come back and run like a sub 2hr 30min then I'd like to do it.
"I'm not saying I could win London or New York but I would like to just run one more and finish on my terms. I'd just like the chance.
"London would be my sentimental choice. It's where I started my career, my dad ran it when I was a kid, and then there was missing out on the Olympics at London 2012."
So next up, body permitting, the swansong.
It's an odd phrase, swansong. It was current in ancient Greece, referring to the ancient belief that swans - habitually silent or discordant - sing a beautiful song in the moment just before death.
How will this innately sweet and mournful image fit the events of April 26 for the world record holder? Well, one hopes. While remembering the physical frustrations which Radcliffe has had increasingly to endure in her running career.
It raises the question of what is the best way for an athlete to bow out?
Herb Elliott. Now there was a man who did it perfectly, surely? The rangy Australian retired in 1962 as Olympic 1500m champion and world record holder, unbeaten in either the mile or metric mile. Tick the box. Job done.
But Elliott's last race was a half mile in 1962, representing Cambridge University against the Amateur Athletic Association. He had been talked into racing, and felt it would have been rude not to. Overweight and unfit, he finished a distant last.
By that time, Elliott's world mile record had been beaten by the rising force in middle distance, New Zealand's Peter Snell, who had won the Olympic 800m title in 1960 and went on to do the Olympic 800/1500 double at the 1964 Tokyo Games.
Snell shocked the athletics world when he announced his retirement in 1965. His final track action took place as he toured the United States. In one of his final races he was beaten over the mile by 17-year-old Jim Ryun - the rising force in middle distance, and the Olympic champion who never actually was.
Getting out at the top, it seems, is easier said than done. Michael Johnson, as you might expect, managed it, finishing an illustrious career by taking the 400m gold at the 2000 Sydney Olympics. But it's a relatively rare trick.
Had Radcliffe wanted to do the same, she would have had a problem knowing where the top was. In retrospect, she could have called it a day after the 2003 London Marathon. But then two years down the line she became world champion in Helsinki - her only global marathon gold.
Whatever the retrospective debate, she is well served in being able to choose an event in which to officially bow out. Many great athletes, including some of Britain's best performers in past years, have not had that opportunity as injury, illness or international selectors have applied the coup de grace.
I saw Sebastian Coe's last race, at the 1990 Auckland Commonwealth Games. Running over 800m, the distance at which he held a world record that would stand for another seven years, the double Olympic 1500m champion faded to sixth place in the final. Despite being well placed around the final bend, the old detonation never happened. Coe's challenge, it turned out, had been undermined by a virus. And that turned out to be his last track competition.
The other two parts of that famed British middle distance triumvirate, Steve Ovett and Steve Cram, also ended their competitive careers with a whimper rather than a bang.
Ovett's last track race turned out to be a 3000m at Cardiff on May 18, 1991. Cram finished by winning an 800m in his native Jarrow on June 8, 1994, in 1:50.3.
Sally Gunnell, who finished 1994 as world, Olympic, European and Commonwealth 400m hurdles champion and world record holder, effectively went out on her shield as she came back from injury in time for the 1997 World Championships, only to injure herself again warming down from her heat victory, subsequently announcing her retirement.
For Roger Black, double European 400m champion and Olympic silver medallist, the decision to call it a day was effectively made by the selectors who chose 200m specialist Solomon Wariso ahead of him for the only remaining place at the 1998 European Championships. Wariso ran out of his skin in the trials, but was disqualified at the Championships.
Radcliffe's contemporary in the British team, Kelly Holmes, was also able to announce her "swansong" a year after her 800/1500m double at the Athens Olympics. She picked the 800m at the Norwich Union British Grand Prix in Sheffield, and much razmattaz accompanied her final appearance.
But Holmes had been troubled by a recurrent Achilles tendon injury for most of the year. She limped home last in the 800m and had to complete her lap of honour on a TV camera buggy.
Fingers crossed Radcliffe's last hoorah goes off more smoothly...
Mike Rowbottom, one of Britain's most talented sportswriters, covered the London 2012 Olympics and Paralympics as chief feature writer for insidethegames, having covered the previous five summer Games, and four winter Games, for The Independent. He has worked for the Daily Mail, The Times, The Observer, The Sunday Correspondent and The Guardian. His latest book Foul Play – the Dark Arts of Cheating in Sport (Bloomsbury £8.99) is available at the insidethegames.biz shop. To follow him on Twitter click here.