Porting from Sprint to Verizon BYOD

I'm a long-time Sprint customer looking to jump over to Verizon. I'm trying to understand what my options are. I'm looking to buy a Verizon iPhone 6 outright without a contract, then activate that device on the Verizon network.

Can somebody confirm that I'll be able to both port my existing Sprint phone number to this new device, and that I'll also be able to get 4G LTE service.

Are there any other limitations? What happens when I'm away from an area with Verizon coverage? Does it roam onto another network, or do I just lose coverage? Is my best-bet to go with their "All Set" pre-paid plan?

http://www.verizonwireless.com/wcms/consumer/shop/prepaid.html

Thanks very much for helping me understand.