I have found that if I maintain some semblance of paddle fitness (sport specific exercises) over a periods of time I can usually be race ready in 4 months. I have found that once I had a solid base of 2 training cycles I was able to reach my previous fitness goals in about 16 weeks of focused training.
FACT: To the degree of fitness that was once achieved is to the degree of that base fitness. This means that something gained is never lost. It also means that training can be picked up where it stopped and can be reclaimed from where it was peaked.