I took Organic 1 in a 5 week class over the summer. Id not taken a science in 2 years, id not taken gen chem in 3 years. I was taking 2 other classes concurrently. I ended up getting a C and I was extremely proud of it. Everyone was failing, everyone was dropping the class, it was hell on earth. If you do it, make sure you are in an optimal situation for it. Make sure you are a good student, have good study skills, are fresh on general chemistry concepts(it helps), and not taking other rough classes during this time period. You need to just make organic your life for the next 5 weeks.
Depending on your prof, it will be an ordeal usually. Something you can look back on and say, wow, that woke me the hell up. I wish I had done better but I got in over my head when I was not focused as a student.