When it comes to political bodies such as councils, 'do nothing' often seems to be the default position, and where it isn't, you'd often wish it was!
With a combined population just shy of 20,000, Cranleigh, Bramley and Wonersh probably don't justify the expenditure required to re-open the line based on immediate catchment, so any case for re-opening would have to be made on the basis of overall benefit to the area's transport infrastructure by proving a need on economic grounds. Social considerations back in the 1960's would probably have been enough to save at least the portion between Cranleigh and Guildford, had these been grounds within the criteria of the Beeching Report, but I fear these alone won't be enough to justify re-opening.
If the line were to successfully serve the catchment between Horsham and Guildford in order to reduce congestion, then Cranleigh's comparative inaccessability by road remains an issue. Commuters would still need to access a new station as their car/rail interchange, plus local buses (such as they are) would require re-routing to serve the line. With the extra strain which this would place on the local roads (such as they are !!), it would defeat many of the objectives of re-opening. That remains a problem right down to Slinfold, and if you're going that far, then why not bite the bullet and re-open the whole line?
I agree, roads in the area are wholly inadequate, and if any scheme for re-opening can address the issues above, then it stands a good chance of being taken seriously. Unlike many other proposals, services to Cranleigh would slot quite neatly into timetables and would actually make operations easier at Guildford.