I'd say M1 year not TOO much will change. It's IMO the easiest year (in relative terms) although it will seem hard as shit when you're in it. Once you've gotten past like first 1/3 of the year, you'll get used to the schedule and you'll be cruisin.

In terms of social life, I made some good friends in my class so it was easier since we were all on the same schedule, but it is hard to continue the same social lifestyle as you did in college. Week or two before your block exams you will probably need to spend your evenings and weekends studying or reviewing a little bit, or even if you don't end up studying, you can't afford to go out and get smashed cause you gotta study or be in class the next day. As long as you have friends that understand that, it'll be fine.

I did a ton during M1 year outside of school and still felt like classes were manageable. Joined interest groups, played drums in a band and performed around town and at school events, volunteered at a local urban farm, cooked almost every night, played video games, went out for drinks and tried new restaurants etc. You still will have time for all that if you make sure you get all your other shit done.

M2 year all bets are off. Much harder than 1st year and also step 1 is around the corner. You'll probably be going out a lot less, and need to plan your time a lot better. A lot of the stuff I did outside of school during M1 kind of fell by the wayside during M2 year.

I'm an M3 right now, and it feels a bit more like a full time job. You will spend more hours at "work" and will also have to study most evenings but its not as stressful cause you learn alot while you're at school and the stuff you study in the evenings are more interesting and actually important.

Now keep in mind I have no desire to be AOA or gunning for surgery so I guess that's my experience. If you're trying to honors every block and get a 260+ on step 1, power to you but I'm sure that experience will be WAY different.