Hong Kong to Shanghai
1900km
23 days (November to early December)
Weather in the south was very hot. I got sunburnt. After two weeks it was cold. On my last day the temperature near Shanghai ranged from +2 to -3.
I underestimated the maps I'd need to navigate through cities. I didn't realise so many roads would welcome bicycles but then become motorised vehicle only roads with no warning or way to divert to other minor roads. I didn't have access to reasonable scale English language maps of the countryside (for the most part they don't exist). I underestimated both the hot weather in the south and how cold it would be in the mountains and closer to Shanghai. I bought my bicycle the day before my trip and it didn't occur to me that the seat post was incredibly short and couldn't be extended any further-- luckily I was able to buy another in a small town where they sold folding bikes with long seat posts.
I really wish I had the $2 compass bell for navigation which I rely upon so much but foolishly (trying to save weight in every possible way on the plane) didn't bring because I thought I'd buy another in HK. They are a dime a dozen in Shanghai but I couldn't find one anywhere in HK or along the way. I thought I could burn 56% alcohol in my Trangia stove. I was correct (in the south) but didn't realise it wouldn't stay lit once the weather became cold. Tent was useless (I slept in abandoned buildings) but very helpful to wrap myself in because I stupidly only had a 10 degree sleeping bag and it wasn't warm enough.
Did right: I bought foam handlebar grips along the way for the handlebars and bar ends ($1 for a pair). The cushioning effect and comfort made a huge difference. I bought a front basket and was amazed how convenient it was. The army surplus bag I brought from Australia and system to attach to rear rack worked perfectly.
I wasn't close to 100% comfortable a lot of the time. But learnt more in the trip than all the internet research I could do in a lifetime. I learnt an incredible amount on what to do in the future.