We show that it is possible to combine an early phase of String Gas Cosmology which can explain the origin of the observed structures on cosmological scales with a short later period of power law inflation which creates spatial flatness . The resulting model is consistent with the “ swampland criteria ” and the constraints coming from the Trans-Planckian Censorship Conjecture . Such a construction is not possible using only canonical slow-roll inflation , but it can emerge in the warm inflation scenario or in cold inflation with an exponential potential . The resulting cosmology is non-singular . We discuss the spectrum of cosmological perturbations resulting in our scenario . On large scales ( scales which remain larger than the Hubble radius after the initial string gas phase ) the spectrum is determined by the thermal string gas fluctuations set up in the primordial phase , and it is almost scale-invariant with a slight red tilt . On small scales , the perturbations produced during the inflationary phase dominate . On these scales , the spectrum is once again nearly scale-invariant . There is an intermediate range ( scales which enter the Hubble radius during the period of inflation ) where the string gas fluctuations are damped but continue to dominate over those produced during the period of inflation . On these scales the spectrum has a sharp red spectral index of n _ { s } -1 \sim - 2 .