First of all, congratulations!
You would have received information regarding pre-arrival programs (funded by IRCC) in both your PPR email as well as along with CoPR. You can join one of their online/in-person session to get detailed information about life in Canada (Employment, Banking, housing, driving, documentation, etc.).
To answer your questions:
The best time is very subjective. There is no universal answer to that.
List of essential documents:
- 2 Copies of list of accompanying goods
- 2 Copies of list of goods to follow
- CBSA declaration card
- Proof of funds
Apart from these, you might want to carry additional documents like your (and your dependents) educational records, certificates (marriage, birth, educational/training etc.), child’s immunisation and school records (if applicable), etc.