It is not possible to zoom with your feet for the perspective alters with distance from the subject.

a copy & paste from a post I made in 2006:

*If you try to compose all your shots with a fixed focal length say 50mm what happens is you are very limited in what shots you can capture:  if you move closer to get a tighter framing the perspective also alters and your subject has changed size in relation to the background and vice versa of course. So that great composition that caught your eye and made you first want to capture the scene has gone.
If however you have a zoom lens and stand still having seen the composition you want and increase your focal length to get a tighter framing what happens is the compositional relationship stays the same.

Example: You see a great vintage Bentley car parked in front of a house on the gravel drive. So you decide to capture the scene as you saw it from the end of the drive. Oh but the problem is with your 50mm lens you also get the rusty Ford parked next door. So you move closer to get a tighter framing, now you have got the house entrance and the car, but what has happened is the car is now appearing a lot larger in relation to the house and the scene doesn't look the same at all.
So you go back to the end of the drive change to your zoom lens and use that to get a tighter framing. Voila! The relationship between the size of the house and the car stays the same and you get the picture you saw.

Of course you could always have a prime for every occassion depending on resources - the money to buy them and a willing and strong assistant to carry your kit bag.

And every one said, 'If we only live,
We too will go to sea in a Sieve,---
To the hills of the Chankly Bore!'
Far and few, far and few, Are the lands where the Jumblies live;
Their heads are green, and their hands are blue, And they went to sea in a Sieve.

Edward Lear
http://www.nonsenselit.org/Lear/ns/jumblies.html