Zone system is just 'exposure for the shadows and develop for the highlights'. With an ambient meter, you can get the exposure. You may need to guess or extrapolate a bit, but it can be done. If you are going to use roll film and mix normal minus, normal, and normal plus on a roll, there are tricks here too. Not as much control as sheet film, certainly, but a help. For normal minus you can flash the film a bit to reduce contrast. For normal plus, you can overexpose a bit to push the exposure up the curve and out of the toe. Of course you can switch film or have more than one camera, too. And there is graded paper to help out.
Turns out, at least with my work, most (not all) pictures can be done normal.