Since I live in Croydon, I joined NCN 21 at Woldingham, taking a bridleway through the golf club. However, I don't recommend that route unless you have a mountain bike. It's a very rough track, which is harder to ride on, and I was worried about damaging my wheels when I was rattling along it. Also, it's covered in loose stones, so I got off and walked on the downhill stretch: I was then pulling the bike rather than pushing it, to stop it from rolling away.
I have various Polar gadgets, and here's the altitude chart I got from the software:
(Please ignore the "Intensity" bars in the background. This chart normally includes separate lines for heart rate, speed, and cadence, but I've hidden them to make it clearer.)
There are two weird bits in there (the vertical lines), so I assume that's a glitch in the watch. Apparently it works out altitude based on air pressure, so it can get confused. I haven't calibrated it properly yet; I need to find a location with a known height, so the "sea level" is a bit arbitrary at the moment, but the relative height changes should still be correct. Also, the X-axis is time rather than horizontal distance, which means that the "hills" are a bit deformed, since my speed isn't constant. If it takes me ages to crawl up a steep hill then it will look like a gentle slope on the chart, whereas if I zip downhill at high speed then it will look steeper on the chart. So, if any of the uphill bits look steep, bear in mind that they were even steeper in real life! Still, for the most part that looks pretty accurate, and there were certainly some nasty hills early on, but I made it up every hill without getting off the bike.
My top speed today was 49.2 km/hour (30.8 miles/hour): yee-hah! Unsurprisingly, this was on one of the downhill sections, when I dropped 14 metres (vertically) in 315 metres (distance travelled, not horizontal); I think that counts as a 4% gradient.
Regarding luggage, I had two rear panniers and my bar bag, weighing 10.5 kg altogether. This is more than I needed for today's trip, but I wanted to get used to the load that I'll have on a longer tour. However, I also neglected to take a few items that would have been useful: a spare battery for my GPS, a compass, and some plasters.
I have a speedometer on my bike (a magnet clipped to one of the spokes of my front wheel), which relays speed and distance to the Polar watch. If I'm on a bike without a speedo, I can use my GPS to record speed/distance as well as tracking my route. If I use both, the speedo tracks speed/distance and the GPS tracks my location. I don't use the GPS every day, because it takes a while to acquire a signal from satellites, and I already know the route(s) for my daily commute. However, it's useful for a trip like this where I'm exploring new territory; if I get lost, I can look back afterwards and figure out where I should have gone. Unfortunately, the battery went flat about 10 minutes into my journey. Normally it would warn me in advance, but I haven't used it for a while. So, I ought to carry spare batteries with me.
I used my A-Z to get down to Woldingham. Once I joined NCN 21, it had regular signposts, so in theory I didn't need a map at all after that. In practice, there were a few problems, so I took a couple of OS Landranger maps with me. I completely lost the route at one point, but I could see a signpost with the road name, so I referred to my maps. Unfortunately, neither the Sustrans map nor the OS maps include that level of detail, so I only had a vague idea of where I was relative to the route. Potentially I could have oriented myself based on landmarks, but I left my compass at home so that was a non-starter. I followed signposts for the "Surrey Cycle Route", which took me in the right direction until I saw another sign for NCN 21.
I also had a "clipless moment": I was turning my bike around, and slipped over on the loose gravel surface. That term is a bit of a misnomer, since my Brompton pedals don't have clips (toe cages), but I wouldn't have the same problem there. Basically, I tipped over to the right and my right foot got stuck on the pedal so I couldn't break my fall. I wasn't really injured, but I was bleeding a bit, and I think I'm going to have some scabs on my elbow/knee after this; that hasn't happened since I was a kid at school! So, plasters would be useful, and I'll take along a few extra first aid supplies on a longer tour since I could wind up dealing with a casualty in the middle of nowhere.
I mentioned the signposts, and they weren't all as obvious as I'd have liked. (I don't have a functional camera at the moment, otherwise I'd have taken photos to illustrate this.) In one case, the signpost actually pointed the wrong way at a junction, so I backtracked when I hadn't found any more and just guessed at the next direction. Normally the signs were paired up, e.g. "This way for Gatwick, that way for Greenwich." However, there were a few cases where they only had a sign pointing back the way I'd come, with nothing to indicate which way I should go. When this happened, I applied deductive reasoning: the sign wasn't directly useful to me, but it was intended to be read by people who were going in the opposite direction. So, if I worked out where they would be in order to get the best view of the sign, that's where I needed to go. In one particular case, this was the only hint I had that I was supposed to turn off into a side-road at a T-junction! In other cases, all I could do was peer off into the distance and try to spot the next sign.
I support what Sustrans are doing, but their routes aren't perfect. I'm going to use NCN routes on my LEJOG trip as much as possible, so it's good to be aware of these issues. Similarly, this isn't like my commute where I can gradually refine my route: I'll only be doing it once, so I need to "budget" time for getting lost along the way.
According to the Sustrans map, it's 26 miles from New Addington to Crawley, then 25 miles from there to Brighton. I didn't start at New Addington, but I assumed it would be similar for me, i.e. 50 miles altogether. When I was in France last year, my touring speed was 15 km/hour, which is roughly 10 miles/hour, so I figured that this trip would take me 5 hours. Sunset was scheduled for 18:00, so if I left at 10:00 then this would give me plenty of time, allowing for a lunch break and going for a quick dip in the sea when I reached the coast.
Unfortunately, things didn't go quite according to plan. I wound up leaving at 12:00, and I reached Three Bridges (near Crawley) at 16:15, where I swapped from NCN 21 to NCN 20. Based on that, I wouldn't reach Brighton until 20:30, by which time it would be dark. That's not a huge problem, since I regularly cycle after dark when I'm commuting. However, it's not ideal if I'm trying to follow a new route; similarly, I like the idea of night swimming, but not if I'm in unfamiliar water on my own. So, I decided to end my journey there and catch the train back to Croydon. It took me 4h15m to cycle down there, then 45 minutes to get back. (As a side note, the train ticket was quite pricey: £7.40!)
That's disappointing, but I'll try again in a couple of weeks, and it will hopefully be a bit warmer by then. As for today, I've been able to explore a new route, and I went 47.3 km (c. 30 miles), which is a respectable distance. I recently came across the 39 stone cyclist, who is quite inspirational, and one of his ideas was to cycle a marathon every day (roughly 26 miles). According to the Polar gadgets, I burnt off 12,364 kJ of energy. According to my bathroom scales, I need to eat 15,966 kJ to maintain my current weight, i.e. that's how much energy the scales think I'm burning every day just by being alive. So, if I can do a similar distance every day, it should help me to slim down. As for today, it was nice to get out in the countryside and see some wildlife (rabbits and swans).