Not either or
A communications network is a must of course. It is a prerequisite to any MERs armada, but hey a boatload of these babies roaming around Mars is a pretty cool idea. Land a few in Valles Marinaris and a few more on/in Olympus Mons. The satelite network would make it possible.
As for staff, I know the JPL team released a majority of the staff after the first 90 days. The MERs could be run on a skeleton crew, and there would be plenty of volunteers to take the training course.