OK. How lame is it that I asked you for info and then took two weeks to respond? Sorry.
For starters, you have 24 weeks which if it were me, I would break down into three phases. 11 Weeks of Base (starting now), 10 Weeks of Race Prep, and 3 Weeks of Taper.
There are a lot of Base programs (i.e. Mark Allen's Low-HR plan). For an Olympic, I wouldn't make it too complicated. Eight to ten hours per weeks is definitely sufficient though it sounds like you do a lot more swimming than I would. Just keep your effort low and resist the urge to chase down the rabbits who pass you while you're running or biking. If you can, get in a long ride of 2-3 hrs and a long run of 60-90 min every week. I find that these are the key builders while the rest of your workouts are pretty much just maintenance. If a "solid run" is a 9 min pace, you should probably be doing your base runs around 11:30-12:00. I know that sounds painfully slow...and it will feel like it the first few times. Trust me, it's the right thing to do. Google McMillian Running to check out a cool tool.
Your goals for the Base phase are to build your aerobic engine (think of yourself as having a big diesel engine that can chug along forever) and to stay injury free. If you feel tired, sick, or just like you don't want to work out one day...skip it. It's not a big deal so long as you don't make a habit of it.
When you get to the Race Prep phase, most of your workouts will be pretty similar but you will throw in some intervals to train your body to go faster. Since you'd like to avg 18 on the bike and 8:30's on the run, here's what I recommend. Designate one day per week as interval day and swap bike and run each week. Something like this:
Week 1 - Bike Intervals - 4X 3 min @ 20 mph with 2 min rest in between each interval
Week 2 - Run Intervals - 4X 1/4 mi @ 2:00-2:05 (8:00-8:20/mi pace) with 2 min rest
Week 3 - Bike Intervals - 6X 3 min @ 20 mph with 2 min rest
Week 4 - Run Intervals - 6X 1/4 mi @ 2:00-2:05 with 2 min rest
Week 5 - Bike Intervals - 8X 3 min @ 20 mph with 2 min rest
Week 6 - Run Intervals - 8X 1/4 mi @ 1:55-2:00 with 2 min rest
Your interval goal for the first six weeks is to get your body used to riding and running faster than your race pace. Part of the reason for this is because once you're out there 18 mph and 8:30/mi won't feel like you're red-lining (because you won't be). Remember to incorporate warm up and cool down into these workouts and adjust them to reflect your ability. If you find they are too hard, cut back an interval or change up the pace. These are just guidelines.
Week 7 - Threshold ride - 30 min @ 20 mph
Week 8 - Threshold run - 3 miles @ 8:15
Week 9 - Threshold ride - 40 min @ 20 mph
Week 10 - Threshold run - 5 miles @ 8:15
Now it's time to start your taper. Don't fall into the trap that most people do and use it as an excuse to stop training because you're tired. You still need to do your long ride and run every week, just cut the mileage a little bit. You still want to do a little bit of speed work but not as many intervals or shorten their distance or even take a little longer rest.
I'm not a coach so take this just as how I would likely prepare for that race. Modify it to suit you and most importantly, enjoy your workouts as much as you plan to enjoy the race. Once you've crossed the finish line, Ironman Hawaii 70.3 on the Big Island will only be a couple of weeks away and you'll be in great shape to do it. I highly recommend that race
