There are plenty of jobs that aren't desk jobs, or at least not entirely desk jobs. It will depend to some extent on what MPH track you pursue and how you sell your experience.
Environmental health, in particular, has a lot of opportunities for field work - collecting samples, doing inspections, etc.
Health education also has a lot of opportunities for interpersonal interaction.
If you are interested in International Health, that may be a good way to get out into the world as well. Running a field clinic? Administering vaccines? Etc.?
I'm probably missing something obvious...but most public health jobs do require at least some paperwork, since there's an emphasis on accountability, and the funding sources necessitate it.
Some caveats:
1) with a JD, you might be "typecast" for a paper-intensive job, so you'd have to play up the wanting-to-move-around thing
2) with some exceptions, the desk jobs are the higher-paying jobs, if this is a consideration
3) unless you're a "technician" level employee, and even then, there will probably be paperwork that needs to be filled out to account for use of grant money, etc.
What aspects of public health interest you?
