Routing and spectrum allocation (RSA) involves simultaneous path selection and contiguous frequency slot assignment, subject to spectrum continuity and non-overlapping constraints. Under these constraints, the RSA problem is known to be NP-hard. It is typically modeled using either node-link or path-link integer linear programming formulations. The node-link model used in this work selects directed arcs for each demand and assigns a left spectrum slot to the selected route. In contrast, path-link formulations rely on predefined candidate routes, leading to more compact models whose performance largely depends on the candidate path set. In this work, we compare several path-generation heuristics against a node-link reference formulation for solving the RSA problem.