spouse travelling on H4 before or after H1B holder visits

I am holding H1B visa and my wife is holding H4 visa. My son is studying in california on F1 visa. Before my employer calls me for the first time to join them in USA, can my wife go on H4 to stay in California. Is her visit and stay linked with my travel and stay in USA. Is there a mandatory stay for H1B holder for minimum period in USA for continous stay of dependent H4 visa holder till the validity of all the visas. If I travel on H1B and come back, can my wife travel and stay on her own plans irrespective of my travel and stay plans in USA.

In this case, H-4 visa will be used for a purpose different from what it was issued for. H-4 is a family reunion visa inteded to reunite the H-4 dependent w/ primary H-1 visa holder.

As you will not be traveling to US, she will go alone on H-4 which in a way is misuse. Also, if you leave US then your dependents should also leave US in a timed manner. The dependent visa cannot be used to “park the family” in US.