@Lethal` is your man for that area I believe.
Not rode there so much in recent years but certainly know the area well!
@Martynt74 Might be a bit late seeing this but quick glance at your route and some thoughts:
- Are you road cycling or off-roading? On the return I'm fairly sure you've turned off on Copsem Lane before the A3 onto some vague gravel. Most of the stuff round that area is doable on a road bike but really not ideal especially if it's been wet. If you intended to be just on road, I'd carry on under the A3 and take the Sandy Lane to Fairmile/Cobham area and head in via Fetcham. I really don't know the suburban area you've headed into via the off-road stuff around Ashtead.
- Even on the route out you're heading through Epsom Common - more off-road. Your route to the back of Box Hill at Headley is rather uninspiring. It's typically used as a quick return to London, it's not particularly fun to ascend. Though the section from Headley to Mickleham is fine. That's a nice road.
- Regardless, heading to the Thames only to go through the Urban sprawls of Surbiton, Hook and Chessington are less than ideal. I'd start and end in Esher without a Thames detour (unless you go properly to Hampton Court and visit Bushy Park).
- Your descent after Box Hill Village down Pebblehill Rd is not particularly nice. It's busy and a very rough surface, then you just end up on a main road back into Dorking.
- Did you know you can actually climb up through Denbies Vineyard (all paved too!)? I'd really recommend it, it's a bridleway so it will have the occasional walker and likelihood is they will have the gates closed so you will have to dismount twice but the views are good.
I think it's tough to suggest reasonable adjustments to the route so I've redesigned it for you. Of course take my advice with pinch of salt - the existing route may be exactly what you fancy but hopefully the above provides some quick insight.
It's only 32 miles but much much better.
https://www.strava.com/routes/2896541891303537376
This will take you out to Surrey via Sandy Lane into the Fairmile area of Cobham (think celebrity houses... some huge places!) and then past Chelsea football training ground on the way to Fetcham. Then you'll dip skirt along to Great Bookham before heading into the proper hills. First up - descent of Chapel Lane, it's steep - be glad you're going down it but do cover the brakes. You'll be deposited out around Westhumble just before the dual carriageway below Box Hill, cross this and you begin the Box Hill climb from the roundabout. You'll turn right a few hundred metres further up onto Box Hill. Enjoy the climb, go round to the viewpoint and take a few photos before descending the same road again. The descent is nice. Much better than the Pebblehill Lane. Head back onto the dual carriageway or if your rather take the rather nice cycle path to the west until you get to Denbies. Pop into Denbies as planned. I've never actually stopped there myself but ridden through it many a time. As you exit Denbie's car park immediately turn right for the bridleway behind Denbie's building. You'll see it ahead heading up through the vineyard. Keep going up, you'll pass through two gates. Just before the end there is a right turn onto a little rocky/gravel path. This is the sacrifice for the nice climb. Be sure to look back as you climb up Denbies as the fews are kinda behind you!
After you get off the gravel you'll be at Ranmore Common. There's two other routes up to this point - Ranmore Road and Ranmore Common Road. Could be worth a try if you fancy a short extra climb. Otherwise head along the ridge until you get to Critten Lane. I really quite like this descent. Relatively flat but kinda open and easy to smash down. Enjoy it. Once you get to the end there is a bakery called "The Bakery" if you need any refreshments. Otherwise carry on heading along until you go through Effingham Common, into Cobham, and then take the traditional Londoner heading out to Surrey route along Portsmouth Road back into Esher (albeit you'll be heading the other direction).
If you want longer than 32 miles I'd advise something like this:
https://www.strava.com/routes/2896544048354673764
This will carry on and skip the Critten Lane descent in favour of heading down Crocknorth (another steep one). Then you'll take the nice climb of Green Dene up to Staple Lane before descending that into the East Clandon area. This is a fun descent. Just be careful at the ~90deg bend half way down - some drivers cut the corner a bit. From East Clandon you'll take a nice route along the lanes back into Cobham.
Opposite Critten Lane is Whitedown Lane. This is generally regarded as one of if not the hardest "Surrey Hills" hill. Pop down it and back up if you want
Other options would involve going south of Ranmore Common/Denbies and heading up to the likes of Leith Hill or Whitedown Lane. I don't have time to plot those right now though!
Apologies for the word splurge but hopefully you enjoy the ride!
It's certainly worth riding if only for the view. The climb itself does get bigged up as if it's some alpine route so that's why it gets stick. It has two switchbacks but it's far from tough.