I added miles in 20-25 increments. My thought process was (in your case) I did 27 km so I KNOW I can do that....so I'll just add another 27 kms. If that works for you, you would be doing a metric century in 4 wks give or take.
and I gotta ask coz darn it Audio - now you've got me thinking: how far is an imperial century?
does anyone know of any Long Distance Riders Anonymous meetings in my area?
Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body, but rather to skid in sideways, champagne in one hand, strawberries in the other, body thoroughly used up, totally worn out and screaming: "Yeah Baby! What a Ride!"