Stephen's mental dustbin
I've cycled to London from Cambridge twice in the last month-and-a-bit, over two mostly different routes, so here they are. In both cases, I went on-road as far as St Margarets and then mostly off-road on the Lea towpath to get inside the M25, so the interesting route differences are in the first section. Of course, I'll rant about the second section too, in just a moment.
The first route, shown in red on the map, is based on this one, as far as St Margarets. The B1368 is a nice route, and is really fairly quiet once you cross over the A505. The hills between there and Barkway (and a little beyond) are fairly hard work, but not destroying if you pace yourself. The rustic section between Puckeridge and Wareside is particularly pleasant, but getting from Wareside to Stanstead Abbots on the bridleways (as in the link above) is not for the faint-hearted. You really need an off-road bike, and since I don't, I wouldn't take that route again---it's bone-shakingly bumpy, and steep enough that I had to get off in places. The immediate alternative is to take a large detour into Ware, as shown on this map, and while it looks excursionary, it's probably quicker and more pleasant for most bikes.
Second time around, and shown in green on the map, I tried Tom Anderson's route (reversed) to get to St Margarets, with two notable modifications. Firstly, instead of taking NCN 11 between Great Shelford and Ickleton, I went through Little Shelford, Whittlesford and Duxford. This avoids the sections alongside the A1301, which as usual are a reason to distrust the NCN. Secondly, after Brent Pelham, do not attempt to reach Furneux Pelham along Violets Lane unless the weather has been extremely dry. It turns out that Violets Lane is the longest ford in Britain (perhaps in Europe?). It's essentially a track along a river-bed, intended to be passable only on horseback (the sign says “unsuitable for motor vehicles”, and that doesn't mean bikes are okay!). It certainly wasn't anywhere close to passable by bike when I went there---fine water-worn pebbly gravel gave way to mud, thick mud, then stagnant water. At that point I ventured no further, but I imagine the stream would have been flowing once my hypothetical Land Rover travelled a bit further south. Unless you're in a Land Rover or some serious off-road motorbike, or on a horse, attempting to get through it will prove somewhere between comical and dangerous. It's rather quaint that sections of our public highways retain that designation even when horseback is the envisaged mode of passage (with “motor vehicles” having been advisorily ruled out). On a wet day the ford is really quite spectacular, as this and this and this and others will attest, but This village walk suggests that with wellies you can get through the ford okay on foot on a not-too-wet day, but that doesn't mean I'd take my bike through, given how easily my mudguards got clogged. From the same village site, this is the rightful flip-side of all those Land Rover videos.
The first time I tried the Lea towpath, I got a bit lost on the way towards Waltham Abbey---having missed NCN1's left-turn away from the river, I ran out of path and ended up taking the B194 through Lower Nazeing. “Nazeing” is a strange name for a place, and I spent a while wondering what it might mean, before realising that if I had a gavel, nazeing is probably what I'd be doing (all over this land). I certainly can't recommend the B194---it's busy! The NCN is a better option, but as usual, it manages to be stressful, because the poor signage and twisty-turny nature always has you worried that you've missed a turning and lost the trail. Second time round I avoided doing so, even when I thought I had: in some parkland across the river from Cheshunt, the path takes a dizzying uphill zigzag that I was sure indicated that I'd left the NCN and entered a pedestrian pathway, but not so, since eventually the NCN signs resumed.
Grumble grumble... I've grumbled about the NCN enough on these pages, and the grumbles don't stop---NCN 1 is full of dangerous, bumpy, practically unrideable sections, particularly along the river, and the usual difficult-to-follow signage will leave you guessing in several places. If in doubt, keep as straight as you can, and don't cross the river even if a signed London cycle route does so. That's if you want to stay on the NCN---I kept on til Canary Wharf, but in general I would recommend joining the on-road London Cycle Network at your earliest convenience. I was quite impressed with the LCN: the smooth surface was welcome, the roads were consistently quiet, and the signage is good. Even better, the roads have bicycle symbols painted on them at intervals, so you can be fairly sure you're on the right track. My only grumble is that the network is poorly-connected---plenty of cycle-friendly streets are not on the network, and there are lots of gaps between the sections that are. I suppose that's a funding issue, since signage and painted bicycles don't come for free. So you need to be prepared to plan the hops between different LCN sections yourself. Invariably you can do this while staying on quiet LCN-like roads. I hopped between NCN 21, LCN 22 and LCN 25 in this way, which got me as far as two streets away from my destination.
On balance I prefer the second, more easterly route to St Margarets---the roads are generally slightly quieter (although there's not a lot in it), the hills less severe, the villages slightly prettier. Much Hadham is deservedly the many-times winner of Hertfordshire's Best Kept Village award, and there are several other contenders on the route. You could even flip between the two routes if you wanted---Furneux Pelham is a reasonable place to flip from east to west, into Braughing, and Barwick is your last chance to flip from west to east, catching the southern end of Much Hadham. Langley and Hare Street are also connected, via Meesden, or you could avoid the busier section of the B1368 by crossing from Elmdon via Great Chishill into the charming Barkway, avoiding the worst of the hills in the process. Ah, the possibilities for superb cycling are endless....