I can help you develop an idea if you'd like.
What is your plan for the W&D half compared to your other recent half-marathons (i.e. Treating it as a training run or a race)?
For training for the W&D half, what have you been doing lately?
What is your goal for the marathon? Time specific or to finish?
If your goal is mainly to finish and not time, but do you believe is a reasonable time for you to finish?
Are you doing any other runs with the marathon, or the marathon as a stand-alone?
How many days a week can you train?
How much time can you devote on each day?
Do you have access to an electronic device that captures lap pace, or something that captures average pace for the entire distance?
What is your running style (run/walk or continuous run)?
With these answers, we could develop an idea as to how you would want to approach the jump from 13.1 to 26.2.
Ok, lets see...
W&D I will be running like my last 2 halves. I have joked that now its a training run for the full, since I've signed up for that, but it's still the run I had planned. I cant think of anything specific I would do different to make it one or the other.
I usually do 2, 5 mile runs during the week and a longer run on the weekend. Yesterday I did 10.2, last week 13.1, and obviously next week 13.1 too.
Basically I would like to finish in good enough shape to enjoy the cruise after, but if I could break 6 hours Id be thrilled. At this point I expect I will run at least the first half and then some, then do a lot of walking for the 2nd half. But again, I'm not really sure until I actually try this out. I know I can do 1/2 in 2:10. I actually did it in 2:03 last week but that's without crowds, bathroom break, pictures, etc...
Just the marathon then
Castaway Cay 5K
I usually run Tues, Thurs then either Sat or Sun. Other days I do the elliptical.
Week days I do 5 in under 50 minutes, then weekends I should have more time to spend out on longer runs. Im thinking 4, 5, 6 hours blocks at a time may be tough, but knowing its only 8 weekends I'm going to have to find the time.
I have a pedometer on my phone that gives me my minutes per mile pace.
So far, never doing more than 13.1 I run for the most part, but will throw in a little walking. For example last week during my 13.1 I walked maybe 1/2 mile at about mile 9 while I had a gel shot. I do expect more walking for the full though.
)
Except Im not doing the 5K. With January coming quickly and snow probably on the horizon soon, I really want to start seeing what I actually can do and up my mileage, but the C2C medal was my first goal and don't want to mess that up now. So, once I get back from the W&D trip, then I have 8 weekends to start getting serious. 
