Bit late to this, not a sub-forum I regularly visit.
Location grabbed my attention as from about Mile 5 to Mile 60 are roads I know well and regularly ride. Prospect of closed roads appealed but dithered due to cost.
It will be interesting to see if the route is altered, but as the local council is a 'sponsor', they should know what they are letting themselves in for. I notice one major difficult area, the A29 heading north thru Pulborough. In the space of less than a mile, the A29 provides access to 2 churches and 2 supermarkets. I wonder how 'customers' for these services are supposed to access these while the road is closed.
There is also a small stretch of A road to the west of Horsham which appears to require diversion. This should be easier as only a handful of local residents would be inconvenienced.
Presumably, the road closures are monitored by police on motor bikes? If there are 15,000 cyclists, I would imagine it does not take long for the peloton to fragment into many parts. In which case, this must require a huge police presence to keep roads traffic-free, from the front to the rear. Would there be a broom wagon?
For those who are signed up and do not know the roads, one of the pleasures you will miss is climbing Duncton Hill from the north. The downside of this, is errrr, the downside. I would imagine it would be easy to reach speeds of 70kph+. Especially knowing there is no traffic coming towards you. But there is a lovely 270° bend at the bottom. If you are in a bunch and do not know the riders around you, I would advise extreme caution!