In my Bryn Mawr interview, the students mentioned a suggested ~10 hr/wk upper limit on volunteering or shadowing activities. It didn't seem like any of the people that I talked to had jobs, even part-time ones. Obviously, a current or former student would be better able to speak to the pace of the experience, but I think that this gives an idea of how academically focused the students are while in the program. They did also mention that there are interest groups, e.g. wellness, Philadelphia activities, so there must be some free time, and everybody seemed very happy and well integrated with their cohort.
I don't know much about HES because it wouldn't have been a good fit for me, but I imagine that the decision between these two kinds of programs would come down to what timeline you want, how many prerequisites you have already done, how competitive an applicant you already are, and how much advising you think would be helpful.