Well sure, but the majority of your energy spent is fighting to get up to speed while in the atmosphere. A balloon or dirigible or some buoyancy play should be

Well sure, but the majority of your energy spent is fighting to get up to speed while in the atmosphere. A balloon or dirigible or some buoyancy play should be able to get you to a certain atmospheric density regardless of planetary gravity. That cuts the bottom off of the rocket equation pyramid and reduces drag immensely at your 'starting' point.