I suspect the bike course at outlaw would be easier and should be sub 6 comfortably. On that basis 11:45 is very doable and if you can shave a bit off the swim then you should be staring down the barrel of 11:30 at the start of the run.
8000 miles per year - blimey. Is that 21 miles a day or 52 weekly rides of 150 miles. If the latter then the physical damage of 300 miles will be minimal as clearly you have comfy bike shoes, a comfy seat and a comfy riding position. That is you would be unlikely to have personal mechanical issues. Therefore getting back to training would be just fatigue related.
What is the longest you have ridden, what was the recovery like?
I think the ride would have to be done 'easy' with no heroics and eyes on minimal damage and a plan for recovery (food, compression, rest, whatever)
If it is within the comfort zone then recovery is quicker. However it will impact your training.
And agree with Cougie the run hurts less than a marathon if you have ever run a marathon at max effort. Which can be anything from 2:05-4:30, max effort is max effort. You will walk some of the marathon and the muscle fatigue from walking is a lot less than running.
I know my legs are certainly heavier and take longer to recover following a marthon than following an Ironman
In fact an Ironman is pretty easy really and you can probably wing it.
It isn't enough to finish the swim. You need to finish the swim in good shape. If you come out of the swim bang on 2-hours utterly exhausted you start to put a lot of pressure on the bike leg. Some do it but it doesn't make for a relaxing day.
If you can come out of the swim thinking that was a nice little swim, wheres my bike then you should be in better shape for the rest of the day.
Start now, get lots of swimming sessions in. When the weather is better and the bike miles start to build you may decide you can cut back on them a bit if it turns out you can swim like a fish. But you can't easily add extra swimming sessions in the later stages of training.
Look at the swimathon in March/April as a mini-goal. Pick up a little medal and gives the swimming some purpose.