First, you need to finish med school and residency and see what the culture is. PP is becoming less common these days, and starting your own practice versus joining a PP group with ability to become a partner are two very different things. By the time you would be ready to practice GS, if 90%+ of gen surgeons are hospital employed, that will affect your location options, and affect potential referral patterns. Hospital employment will get you a certain amount of business at baseline (usually through call or other hospital employed physicians) until your reputation, outcomes and advertising gets you more business. In PP, you have to advertise yourself to the public and to local physicians in order to get business and help get you the volume to build your reputation.
Second, your take home pay will depend on how successful you are. You will have overhead to include office staff, supplies/equipment, EMR, advertising and malpractice costs. You also will find that your charges =/= your collections, and that some insurers are slow to reimburse.
Third, taking hospital call will be a way to increase your visibility and volume while you are trying to get established. If you are in PP by yourself, you will always be on call for your patients even if not on ER/consult call at the hospital. If you have partners, call is more split up. Hospital call "gruesomeness" depends on 1. how many people are sharing the same call, 2. how busy the hospital is, 3. if you are covering trauma, and 4. how many hospitals you cover. Referral patterns are also important; a well-established group is going to be hard to compete with as a "new guy" in a different practice unless you do something to make yourself the surgeon of choice (whether that be due to fellowship training, availability, etc., something has to make you stand out)
tl;dr: wait until you are almost done with training. No need to decide until you are at that point in your career. There are many variables involved and your perspective will likely change as you gain experience and training.