I did the marathon on Sunday too and thought it was pretty well organised and thought the support was great around the course. The last mile or so especially seemed good to me, but it was my first marathon, so maybe others are better. There were a few miles towards the end of the out and back part where there weren't many supporters, but the sea view and the off-road part made for a nice alternative.
I didn't pre-book the bus and instead just got one from right across the road from the school so didn't have to walk far at all. It was only £2 which seemed pretty good value, but it did take about an hour to get back to the centre of Edinburgh due to traffic (and that the bus driver seemed to give way to every other vehicle on the road!).
I'm definitely going to do again next year as love Edinburgh and know I can go faster with a bit more training - ideally some of it in warmer weather than this year! Think I may have got the marathon bug.