The propagation of small bodies in the solar system is driven by the combination of planetary encounters that cause abrupt changes in their orbits and secular long-term perturbations. We propose a propagation strategy that combines both of these effects into a single framework for long-term, rapid propagation of small bodies in the inner solar system. The analytical secular perturbation of Jupiter is interrupted to numerically solve planetary encounters, which last a small fraction of the simulation time. The proposed propagation method is compared to numerical integrations in the solar system, effectively capturing properties of the numerical solutions in a fraction of the computational time. We study the orbital history of the Janus mission targets, (35107) 1991 VH and (175706) 1996 FG3, obtaining a stochastic representation of their long-term dynamics and frequencies of very close encounters. Over the past million years the probability of a strongly perturbing flyby is found to be small.