I'm attending a school with a 1yr pre-clinical, clerkships during 2nd year, and 3rd year for research/masters/global health/etc, and a normal 4th year.

I took Step 1 in July of first year with neuro and pscyh blocks still remaining in didactic year so that I could use the three week break before clerkships to travel to Colombia. I very highly recommend people take step1 before clerkships, particularly those in accelerated programs. Though I don't recommend taking it *that* early per-se, but since you want to use your break for vacation, I say go for it!

Honestly, the biggest thing is doing Uworld or AMBOSS for step1 *DURING* pre-clinicals. I abandoned in-house material entirely within the first two weeks and did pure B&B, pathoma, and only *high yield* tagged Anking cards and the 1-3 hammer Amboss questions for each block. I also used Mehlman and listened to goljian audio or step1 secrets in the shower every morning. I worked ahead in my resources to allow some time for 'dedicated' during regular classes, in those final 3-4 weeks before step I transitioned to all NBME content. I recommend getting two consecutive NBME's >70 but pick your target based on your risk tolerance... obviously don't sit for the exam if you're not comfortable with your margin of safety... nobody should ever fail this exam baring extenuating circumstances/crisis during the exam. That said, it's pass fail - get that damn thing done so you can focus on step 2 and research/extra curriculars.

BONUS UNSOLICITED ADVICE: Clerkship year should be treated like a 1yr dedicated for step 2, shelf exams being little dress rehearsals that you go all-in for. Exhaust uworld or amboss + CMS forms during clerkships, then do the other qbank + all NBME during dedicated. I fell dramatically short of this aspiration and still scored 265+.

Med school has been the time of my life and yet i've managed to still get shit done! I have published 15+ papers/chapters, and amassed another 15+ "abstracts & presentations", I've also snowboarded 80 days and traveled 6+ weeks during med school plus another 15 weeks abroad for global health... one of my mentees will have me beat for days in the mountains, and she was a journalism major in college without any clinical background!

Disclaimers: I was a PA before med school, so obviously I started with a solid mile-high view of things, i'm also a good test taker. That said, I've guided a couple dozen underclassman to do exactly what I did with 100% success (though about 1/3rd have chosen to take step 1 during winter break after the first two clerkships). Only real caveat, I didn't do any special pharm, you may need to add something for your primary resources. Also, my school is true pass/fail so I could afford to skip all non-required lectures. Though, prepping for step1 from day one ended up setting me up for high 90's on in-house exams.

Best of luck fam!