Some patients who don't do well on 6mp seem to do better on azathioprine (a brand name is Imuran).
My daughter's first colonoscopy didn't show the terminal ileum because a stricture prevented entry into the small intestine. But the second colonoscopy did go into the small bowel, because there was no longer a stricture blocking the way. So it sounds like your doc was unable to get in because of a stricture right at the end of the terminal ileum.
You had nearly a year without a single flare? No symptoms, either? It really does sound like you might have time to explore options in diet and meds other than surgery, which is not a permanent solution, anyway.
I'm not so sure you have scar tissue, which in my opinion is the only reason for surgery, because it took you so long to have a flare, and the flare resolved so quickly. Even after surgery, you still need meds, so perhaps the focus should stay on finding the right med or combo of meds. Even maybe for looking at LDN.