Using a wide angle lens (170° and more) will capture all detail on each side of the road. That's what we call a POV: Point of View video.
As you can't just go for a ride on a Summer solstice, bear in mind the position of the sun during your ride. Going East in the morning is not the best idea for example.
Use a camera with a video stabilizer or at least make sure that it won't vibrate too much during the ride. If you put the camera on your helmet, try to always keep your head in the same direction.
In general: the higher, the better. A 4K file can always be rescaled to a lower resolution in post production. But think about the space it will take on your memory card, the time it will take to upload, etc.
Compare these 2 videos: they were recorded by Lesley Patterson, 2x World Champion of XTerra Triathlon. Which one do you prefer? The one actually recorded from her bike's handlebars? Or the one recorded by her friend on a motorbike?
Merge several video files together
VideoTaped is a very small and efficient piece of software relying on ffmpeg to merge video files. Most on-board cameras create file chunks of 4GB or less, making uploads to platforms such as Kinomap difficult. Just select the files to merge, define if you want to trim at the beginning and at the end, press the "TAPE NOW" button and generate your finished file. No further encoding is required. VideoTaped can also remove the audio track, and even the subtitle track that sometimes includes GPS data so that you can use an external GPS file for final uploads. Requires Java 1.7 or higher.