Encapsulation questions

Please can anyone confirm my thoughts on encapsulation with regards to transporting data:

1. User has data to send (Layer 7)
2. Layer 4 Information is added = Segment
3. Layer 3 information (IP address) is added = packet
4. Layer 2 information (MAC) is added = frame

a layer sees information from an upper layer only as DATA.

If a frame hits a router, it extracts the packet and reframes it ready for transmission to the next router.

Where my thinking goes off track is regarding Routers MAC addresses, would the router then ARP for the next hop mac address then wrap the packet up accordingly?

What happens when the packet / frame is passed between routers and switches?

Regards

Mark