As Seeline said, a lot will depend on your personal situation and also likes/dislikes. (also, I had to convert that into metres to get an idea 140ft is 42m)
Another important question is how wide is the garden? Is it quite narrow, eg maybe only 30ft (9m) wide, so that you have a long thin strip?
Or is it wider, say something like 50ft (15m), so that it is something a bit nearer to a rectangle?
These things will also play into how you can use the garden.
I know a number of people with long, south facing, gardens who have effectively divided it into two by planting screening plants and/or trees across the garden at about the half way point.
Beyond that point they have a second (or "secret" if you like) garden containing the outbuilding, vegetable plots, fruit trees etc. hidden from the house.
On the side nearest to the house they have it set up as an ornamental garden. How they use that space varies; as Seeline mentioned above it varies depending on their preferences.