really you should ALWAYS be looking for a field
no matter what you fly, where you fly, when you fly...you should be looking for a place to land...just in case.
and if you are on instruments....have a working knowledge of what is nearby, be able to make at least a ''cloud break'' aproach to anyplace within range of a VOR...or enter a holding pattern that you make up on the spot in an area clear of innocents and giving you a chance.
Even in big jetere have been good reasons to just SET DOWN NOW to save everyone on board.
I know one outfit that routinely landed sabreliners on two lane highways.
use your imagination...know the ''glide'' line (see ''stick and rudder)...and know the place below the glide line in the window that you can make.
while flying the line in the DC9 my pals and I would always point out places to land...never needed em...but its fun and keeps your mind sharp.