Hi! We were in your position 2 years ago and living in Weybridge at the time. RGS was probably marginally easier to get to and DS had several friends who were going there, versus none to KCS. However, we all just liked KCS more - our gut feeling was that it was a more welcoming place! There is nothing wrong with RGS and had there been no offer from KCS, we would have accepted RGS without hesitation and I’m sure DS would have been happy and successful there. If you feel really neutral between the two, perhaps a return visit with your DS to both schools would help to clarify your feelings?
Academically, both are excellent of course, and both offer a wide variety of sport, music, drama and many other extracurricular activities. My DS is now in year 8 at KCS and loves it. One difference between RGS and KCS , at least for those first two years, will be the size of the year group - lower school at KCS is small; this was good for my DS, who like many other boys starting there, was the only one from his junior school. The pastoral care has been really good so far and he’s made lots of great friends. The year group will expand a lot next year as they are joined by the boys from KCS prep school plus some other 13+ joiners, but he is looking forward to that too. Someone mentioned fees - they increase from year 9 at KCS but I believe they stay flat from that point through to the end of sixth form (subject to the normal “inflation” increases every year of course!).
Like a another poster here, I also like the fact that girls are admitted in the sixth form (this was not of interest as a factor for my DS!) and the option of IB is also potentially appealing as he has wide interests and may not want to narrow his studies too much at sixth form level. The school is very strong on IB but also on A levels, so it’s just nice to know you have the choice.
So, travel: we used to drive DS from Weybridge to Esher every morning where he caught the bus. It was a reasonably early start but we adjusted! The bus service was good, there were plenty of boys using it and he rather enjoyed that time, whether chatting to other boys, or looking over homework or just relaxing. In lower school, pretty much all activities/clubs are run during an extended lunch hour, so as not to disadvantage boys who need to get the school buses home (and so as not to overtire them!). Occasionally sports fixtures would run late but we would be warned well in advance so we could make other arrangements. So I would say if you choose KCS, the commute from Walton is very doable!
All that said, we had no ties to Weybridge so towards the end of DS’s first year at KCS, we moved to Wimbledon! There’s no doubt that it’s made things easier, but if we hadn’t been able to do that, I feel sure we would have managed quite happily as before.
They are, as others have already said, both excellent schools, and you are in the same sort of geographical position that we were. So unless you are considering moving house, your decision will come down largely to how you or your DS “feel” about the school. You can’t realky make a bad decision here, which is a lovely position to be in! Well done to your DS and good luck with whichever you choose!