I'm a regular runner, I've done quite a few half marathons too. The advice I would give you is to test to figure out how much glucose you're going to need. I test every 30 mins and from that I've figured out that I need 2 Dextro tablets every 15 mins to keep my BGs steady. If you find they're dropping, take an extra Dextro tablet.
Also, always carry your BG meter and extra glucose. I use a CamelBak rucksack, which carries water and it can fit all my diabetes stuff in too.
You'll need to be careful if you are honemooning, as things will start to change for you diabetes-wise, so make sure you test frequently.