Welcome, zracre! We need some clarification: where exactly are you having problems mounting the cable? at the Front Derailleur or on the down tube? Do you have a picture you can post of your problem?

Looking at an '83 Fuji catalog, I can see that there is a cable housing stop clamped to the down tube for stem-mounted shift levers. I can't see from the picture how the shift cable is attached to the front derailleur (surely someone here has an Espree?) so I can only guess how it makes the transition. I'd guess it runs under the bottom bracket via a cable guide to a bottom pull front derailleur. If you don't have a clamp on cable stop, you will need to find one (again, someone here surely has one kicking around in their parts bin).