I take a bus to the library and spend some time there, interspersed with many breaks which involve walking to a nearby tea house. Taking a bus outsources the attention-drain of driving while still being conducive to the trance-like free-floating state of mind in which one can feed the thoughts to the unknown and allow the ideas to come to you.

Most of the times that I have sat down at the same desk for 2 hours, I have regretted it. It's sub-optimal unless you are literally just typing in what is already known.