Help with moving to SF for Summer Internship [Student]

Hello! I recently was fortunate enough to receive a summer internship from May to August for a cool tech company that is located in Tenderloin. I, however, have never visited California, and would love to to have a great summer experience. I have a stipend of 2,000, but I do not mind paying slightly more if that means that I have access to a vibrant community whilst still being within a 30 minute BART ride. I have a few questions and would appreciate any input!

• What are some websites where I can find summer furnished housing that is reliable/not scammy? Is it too early to be looking for apartments right now, or should I find summer housing ASAP?
• Should I try to find rooming with interns who are going to intern at the same job as I will work at, or should I find interns who are working at a different internship?
• Would finding a sublease from a UC Berkley student ruin my summer experience of SF? I want to be able to work hard, but also "play hard" and enjoy my summer while trying to make friends in the area.

A lot of questions, and I am a bit scared to move to a new area, but I would appreciate any insight!