I live and work in Paris, France as a software engineer. My wife is a homemaker. I have a work assignment in Texas, USA in the month of may. We are planning to travel together as the assignment more than 3 weeks. My close friend and his wife stay in San Francisco.
Ideally I want my wife to go to SF and I go to Texas for work for 2 weeks and I would join them in SF , spend 10 days and fly back together.
Can we apply for B1 for me and B2 for my wife together? Or I should B1 first then go for her B2.
Once we apply for my wife’s visa based on my B1, can she fly directly to SF and not with me?
As far as I know, B1 and B2 are two separate VISA categories which have no relation between each other (unlike H1/H4 or L1/L2). The two categories of visa are usually issued together as a B1/B2 visa.
1) Each visa will should be applied separately, but you may do the application process together. However, your B1 will be based on the documents provided by your employer and your wife's B2 will be based on the letter from your friend (sponsor).
2) B2 is not based on B1. Yes, she can travel to SF.
3) You might require sponsorship document from your friend for your wife's B2.
I believe you need to mention the details of your travel in the VISA application (like the visiting places, name and address of your stay, duration etc.). Hence if you plan to visit SF after your business trip to TX, you might want to include that too in the VISA application.
Info on B1/B2 VISAs:
[Visitor Visas - Business and Pleasure](http://travel.state.gov/visa/temp/types/types_1262.html)
[Business and Tourism Visas](http://chennai.usconsulate.gov/tourism-/-business.html)