last summer when our watch showed an interest in getting fit I used to have them perform circuits of drags, carries, med ball throws and various calisthenics, with each station timed, (standard circuit training stuff really, but with decent exercises). If I was in your position doing this for new recruits I would factor in a team aspect to this - eg set up a couple of medleys and have teams race each other through them.
Or I’d just be a twat and have them run hose out until they puked and then make them roll it up again.