Quite a jump up here so I’m not going to start setting targets or pace.
My best advice would be to run the first 5-6 miles on the flat around normal long run easy pace. Then walk the hills.
Then push the pace a little once you hit the flat and downhill section. Hopefully this approach will leave you feeling strong for that last segment.
No clock watching here please or comparisons. The fact you’re taking part in this is great.