Between training plans and stuff....

I am doing a 'dirt' half marathon which is basically up hill for the first half and down hill the second half. This is my first half marathon for nearly 25 years.

I have recently run about 1hr50 for 13.1 whilst running a 15 mile steady run across much hillier ground than the event is over. On this basis I am going to set out to run at 1h50 pace for the first half of the dirt half marathon and something like 1hr35 for the second half.

This is on the 17th November. I am then probably doing the London marathon. My first marathon. There are many training programs on runners world and I am not quite certain what pace marathon to aim for. They are mainly 16 week programs which therefore starts about first week of Jan 2013. My running is still improving from when I started 13 weeks ago so I am uncertain whether to embark on a more ambitious program based on what I think I will run on the day in 5/6 months time from now, or whether I should base it on the dirt half marathon time (albeit off road and probably more hilly), so that's one question I don't know the answer to.

The other question is that after the November 17th half marathon, I have 6 weeks 'to kill' between that and the start of the 16 week London marathon program. What do do with this time? I don't want to 'sit still' and want to push on so that I go fast in the marathon. I did think of trying to do another half around Christmas/New year but there isn't one on - and I can't find a six week program. Any ideas gratefully received!