The Japanese SS520-5 nanosat launcher has a payload of 5kg or so to LEO on an all solid fuel rocket with a total mass of about 2.6 tons. To reach LEO its delta-V totalled over all three stages must be about 10 km/s, which is more or less what is needed to get from Mars surface to Earth intercept. Furthermore it's entirely solid fuel, so should survive the journey to Mars (at least from a time perspective).
Which brings me to my question -- if you had one of these (with reasonable adaptations) on the surface of Mars, could you use it to return a few kg of samples and heatshield to Earth, thereby eliminating one step in the current Mars sample return mission plan?
Secondary (but really part of the same question)? Just how hard would it be to get one there? It's about three times the mass of Curiousity or Perseverance, and a rather awkward shape.