KR- I did a 6 week build up to Amsterdam, the Ultra was 8 weeks before so after that I did 2 easy weeks of 15-25 miles, then did 6 weeks avg. 51miles. I did a weekly 10mile tempo run at 7mm pace, my long runs were 13 (Ashbourne HM), 20, 16, 14, 21 (Redbull Steeplechase). I was also cycling to work 1 day a week which was a 30mile round trip. I personally think the short build up worked for me. As long as you have a good endurance base the marathon specific stuff can come much later in a plan, avoiding peaking too early or injury risk. For VLM I plan to do lots of strength work by doing hilly fell runs, very slowly, but 15-25 miles, a couple of speed session each week and a mid week 10 miler. I will do these without a watch and only come to using a watch and calculating paces in the last 8 weeks.
Fraser - I prefered Berlin to Amsterdam, both are very flat but Berlin was less congested and they wasn't the tramlines and surrounding cobbles in Berlin. I also found the support better in Berlin. That said it was obviously a very quick course in Amsterdam!