Peter Langford, from Suffolk, had already cycled the 1,100-mile (1,770km) route three times - aged 75, 80 and 85.
His month-long adventure has so far raised more than £33,000 for two homelessness charities.
"I look back and think 'how did I manage some of those hills?' he said, adding he would not attempt it at 95.

That’s impressive. I had a friend whose father was 78, and rode 25 miles every day. I hope I’m still riding at that age. I said I would never stop, but rode the fewest miles ever this year. I’m hoping the enthusiasm returns next year.
1100 miles!!??!! Does the route go through Paris? It's only 603 miles as the crow flies, 814 miles if you're willing to brave a few Jacobean-era bridges.