Madbee, the MP miles were tough. I broke them up into 5 x 2mi laps and ran them as loops of a flat 800m promenade to try to keep out of the wind a bit.
It was boring and I kept seeing the same dog walkers again and again and again. They must have thought me insane.
Ramjet, I find that if I back off too much on the cool down my back and hip really start to hurt. My "easy" pace range is 7:30-7:00, so I was in the zone. Plus, I really, really wanted something to eat! Congrats on the successful 5 x1000m.
NE, I'm with Westy. Go for it. If you fail to make it, you'll still run the best marathon you could have. I once went for sub-3 and ran 3:01 - no regrets.