Don't know if it's changed for 2015, but last year the start line was not the finish line (the finish is further down the hill so don't stop early!). It was chuffing freezing and foggy at the start, so lots of people were keeping indoors at the race HQ building to keep warm - allow 5 minutes or so to walk to the actual start from there.
Support is good but there are sections out in the country lanes where it's just the runners, so chance to get in the groove and tick off the miles. When you did hit a village though, the support was fab. Stamford Bridge was a wall of noise.
Way too expensive for a 10k in my book. I know 3 other runners in the family who feel the same as well.
The four of us ran the Budapest Half Marathon a couple of weeks ago and that was about £25 to enter. The apartment we rented was £12 each per night, beer ~95p a pint (post-race only of course)... I could go on but it was a great trip and a really good city to visit.
It seems flying direct Virgin from LHR to Chicago is a lot more expensive than a one-stop out of Manchester (which would save us trundling down to London). £815 return with Virgin, whereas as KLM via Amsterdam is around £625 (even cheaper if you go via Dublin or Paris).
We'd want to go for a week, so look to get an apartment. We've just done that in Budapest for the half marathon and it worked out as £12 each a night. Bargain, though I'd expect it to be more like £90 each a night in Chicago.