A Multiscale GasKinetic/Particle (MGP) computational method is proposed to simulate the plume-crater-interaction/dust-impingement(PCIDI) problem. The MGP method consists of a multiscale gaskinetic (MG) method for gasdynamics of rocket plume-in-vacuum flowfield, an Overlay method for gas-particle interaction. MG combines BGK Gaskinetics (BGK) and direct simulation Monte Carlo (DSMC) methods with a domain decomposition technique to account for various scales of rarefied gasdynamics, covering continuum to free-molecular regimes. The dust particles are modeled by an additional distribution function in BGK, thus carried by the MG-generated flowfield through an overlay method. Dust properties are to be modeled using Discrete Element Method (DEM) simulation, which will lead to comprehensive continuum equations for crater formation. Phase II will extend the present MGP method to 3D, with more advanced dust particle properties and complex crater formulation.