GS is intense. Ortho may or may not be. It really depends of the individual program she’ll be rotating through.
Vacation–does her schedule include dedicated study time for USMLE/COMLEX? If it doesn’t, she should use her vacation to study for boards. 3-4 weeks of dedicated study time is pretty common for Step 1/Level 1. If your D plans to apply to any ACGME (MD) residencies, she must take both exams.
If her schedule already includes dedicated study time, then your D has more options. A brief vacation (1-2 weeks) is pretty normal and nice way to break up her time, esp if she takes it between MS3 and MS4.
RE: slack time-- don’t assume that her rotations will begin and end in smooth lockstep. Since DO rotations are done at several different clinical sites, all running on different schedules, there may be a mismatch of when one end and the next starts. Her vacation time may get eaten up by a week lag here and a 2 week lag there between rotations.
What are your D’s areas of interest for specialties?
If she hasn’t rotated through all of her interest areas, then she needs to do at least one elective rotation in each during MS3. If she has a done a rotation through her area of interest, then she should consider doing a elective sub-I rotation in her potential specialty. She’ll need 1-2 specialty-specific LORs from supervisors/PDs for her residency applications.
She may also want to apply for away rotations (also called audition rotations) at any residency programs she has a strong interest in matching at. These are best done before she applies for residency next June/July. If your D wants to apply to ACGME residency programs, she really, really needs to do one or more aways in her future specialty at a ACGME residency program.
Some specialties (EM, for example) expect/require students to have completed one or more away rotations in the specialty before they apply to residencies. That’s something to consider also.
ERAS opens for DO residency applications in June with PDs receiving applications in mid-July. .
https://students-residents.aamc.org/attending-medical-school/article/eras-2017-timeline-do-residency/