Gap between two employers on H1B

Hi,

I am about to resign from my current company.

I already have approved H1b from my new company.

How long can I take a gap between resigning from current and joining new company?

I have some travel plans within USA

And new company has agreed for my joining on 29th April.

I leave my current compnay on 29th March.

Please help me with this question.

And new comp