Big Long Road

If you build the city as one long road, making sure to wind through import raw material resource sites, then it’s not very easy for your walkers to get lost. Just make sure you have sufficient prefectures and engineers at reasonable intervals along the road or else you’ll find out all about the range of walkers before you know how to handle the resulting problems.

This method is simple but effective, at least for the earliest levels of the game, and everyone has probably considered it at some stage due to the existing “Road from Rome” when you start the levels.