In my terminology, an “awkward” tile is a tile that the Google Streetview car has not entered. Often this means there are no public roads in the tile. The next best things for getting into that tile are public bridleways (which you can ride along) and public footways (which you can walk along). Most county councils publish an non-definitive copy of their “definitive map” online – these are excellent free sources of information on bridleways and footpaths. Here are the ones I use:
See also: Where can you cycle?