It is almost certain that this flutter will come back. They almost always do. Because the ablation is a low risk procedure I would suggesting pursuing it at this point. More importantly, you should continue to follow with you cardiologist even after the ablation because those patients who have atrial flutter also may have atrial fibrillation.
I am also a long time runner and cyclist that has had problems with atrial fibrillation, closely related to flutter. My episodes tended to come on during near-max exertion or from intense emotion situations and last for about 24 hours. I tried beta blockers to prevent them with little or no effect. Now I have been prescribed amiodarone and since I started that I have no problems. I am on the smallest dose that is effective as the medication does have some potentially serious side effects. The doctor prescribed 100mg/day but I do fine with 100mg every three days.
My brother had atrial fib also also brought on by exertion. His did not respond to medication though and ended up having an ablation. He is now fib-free.
I am surprised that your insurance would approve an ablation before you had explored the medical route.