I ran the Edinburgh marathon this year as my first attempt at the distance and very much enjoyed it. I was right at the back of the field though, partially due to being so damned slow and stopping for a loo break at the start.
I was lucky and was picked up from the finish so no faffing with buses but still had to walk a good way to the sports centre car park. To be honest at that point I was finding it more painful to stand still than to walk gently so I was glad of the extra distance in a way.
In terms of support, I find the quiet stretches of races absolutely fine to be honest. It lets me focus and not think I'm being rude for not acknowledging spectators or high fiving the kids. I'm sure that's not a problem when you're in amongst the main body of runners but when they're cheering you on and there's not many runners around you, you feel obliged to interact and it can get a little draining after a while (sorry!!). So I'm quite happy with long quiet stretches as well as the bits with more crowds - a fine balance.
The out and back bit was fine as well. I really enjoyed seeing the elites coming in and didn't at all find it demoralising to see the hordes of runners on the opposite side knowing that they had done a fair few more miles than me - I was looking out for the first purples coming through as then I knew the turning point was closer.
Overall then, I was quite happy and really enjoyed the experience, although again I have nothing similar to compare it with.
I'm looking at this one as well for a potential first marathon and I'm local so would be very convenient. Should have done the half this year but couldn't in the end (just as well as it was such a grotty day they curtailed the full marathon and only allowed people to run the one lap for the half).
Eager to see if it's suitable for a slow first time marathoner!
I read on another forum that someone had measured the Coombe Abbey race and it came up as 8.7k. That would explain why I apparently knocked a full 9 minutes off my previous 10k time (was only my second 10k). Still, I really enjoyed it despite (or perversely perhaps even because of) the thunderstorm!