1. Physics and German were for me the challenging, but it depends on your academic abilities or whether you're more STEM/humanities focused. Both are generally yuk year classes though.
2. West Point and the academies- more than the vast majority of other schools- have a unique relationship between students and instructors. Instructors are there to help you at any time of the day, any day, for the most part. AI (additional instruction) is everywhere, and they are always willing to help you with anything you're struggling in just by making an appointment with your instructor. You could also utilize cadet tutoring, though I find going right to the instructor with questions the best for me.
3. It depends on the weekend. There are three main types of weekends: B, A/C, and A/D. B weekends means you are free to leave and take pass. A/C means there is military training on Saturday morning before lunch and then the weekend converts to a B weekend. A/D means there are formations for upperclassmen with under a 3.0 academic GPA and all plebes for breakfast and lunch, then it converts to a B weekend. If you're an upperclassman with above a 3.0 GPA academically then the whole weekend is a B weekend. There are also F weekends which are football weekends, which you go to the home football game and after the alma mater it converts to a B weekend. The only time this would ever be different is if there is a special event that weekend, such as for plebes when we have plebe parent weekend, for the cows when they had 500th night this weekend, etc. As a plebe you don't get OPPs (off post privileges), which allows you to leave the academy in a certain mile radius (I believe 75 because I know you can make it to NYC under OPPs), so we have to take pass or walking privs (which I've never taken walking privs, it's just a hassle to walk so much in dress grays). You will have a lot of opportunities to get performance passes and take non-chargeable passes (on top of your 1 base pass as a plebe), if you want them. I live in NJ, so I made it home quite a bit last semester and funny enough am currently home on pass right now.
4. It's all mindset. Not just West Point, but the whole military involves having a good mindset. Stay determined with the goal in mind, but live weekend by weekend. Utilize being so close to your best friends and visit people, I pop into my friends' rooms daily and they come into mine just to talk, get dinner, work out, whatever it is.
5. Going off of number 4, MINDSET! Be ready to grind out life on the daily but be positive about it, even when things suck and you're up at 3am prepping for a WPR. Stay positive, don't fall into cynicism like many do. When you take a step back from everything, you realize how special West Point is and how good you actually have it being there (and especially how useful it'll be to slap USMA on your resume). Take advantage of the unique academic opportunities that USMA provides through research and internships (AIADs), and the unique military opportunitites through military schools (MIADs). Also, get involved in a club or sport team or something. Just stay involved. I'm on a really close-knit team and having that second set of family after my company is really worthwhile and opens up even more doors to get away from USMA for a bit, build lifelong connections, and keep myself grounded.
Hope that all helps! DM me if you have any specific questions