In many of my visits to great courses I have been fortunate to have the time to play the course AND to walk around to study it and photograph it. On my trip to the UK, I would get to a new town at mid-day, play the course, walk it and take pictures that evening and the next morning, and move on down the road ... or occasionally, if I arrived late, I would do the photography first and play the next morning after taking pictures.
Now that I look back on it, I'm not sure which is the better approach.
I think most people would say have a walk around first, so you understand the course a bit before you go try and play it. Peter Jacobsen told me years ago he'd rather do that on any new course, so he could see the course the first time with positive thoughts and not form an immediate bad impression of the holes where he hit a poor shot.
But, contrarily, if you play the course first you are seeing it as it's meant to be seen ... and if you screw up the third hole, you will go out later and dissect what you did wrong and form a better impression of the hole in your mind, won't you? And isn't your final impression ultimately the most important?