RXJ1713.7-3946 is one of the most prominent supernova remnants (SNRs) at high energies, with clearly rim-brightened emission from X-ray to TeV gamma-ray energies. Its relatively young age (1.6 kyr) also makes it a perfect example to search for evidence of escaping cosmic rays up to PeV energies. However, the level of gamma-ray emission that might trace escaping cosmic rays depends heavily on the presence of ISM gas clouds around the SNR, the physics of cosmic-ray escape from SNR shocks, and the transport properties of the escaping cosmic rays. We apply here a newly developed 3D model of escaping cosmic rays from RXJ1713-3946 coupled to the measured molecular and atomic gas at arc-minute scales, to assess the gamma-ray emission at several places around the SNR and its detectability by future gamma-ray facilities such as the Cherenkov Telescope Array (CTA). For some model variants, the predicted emission from one of the ISM clouds (north-west of the SNR) approaches the CTA-South 50hr sensitivity in the 10 to 20 TeV energy range.