A Landau-de Gennes type model for the direct isotropic/smectic A phase transition is used to study surface-enhanced smectic ordering in the stable smectic temperature regime. A unified surface-free energy functional is proposed which can be utilized for homeotropic and planar surface anchoring. The time-dependent complex Landau-Ginzburg evolution equations and boundary conditions are derived for thin-film geometry. Simulation results are presented for the two types of anchoring and compared to observations from experiments and previous simulations. Simple visualization software for smectic layering was developed and is also presented that is compatible with discretized numerical solutions of the model.