PCB's and designing power connections
I'd recommend looking at PCB Design Guidelines For Reduced EMI by Texas Instruments.

While it is focused on reducing EMI, it offers advice or answers to all of your questions except "Manhattan Routing".

Section 2.1 (about 12 pages) is about Ground and power. It includes these 
useful sections:  


  2.1.7 Power Plane Do’s and Don’ts for Four-Layer Boards
  2.2.1 Single-Point vs Multipoint Distribution
  2.2.2 Star Distribution
  2.2.3 Gridding to Create Planes


It shows how to get close to 4-layer PCB EMI performance using a 2-layer board. Part of reducing EMI is to ensure there is good power and ground routing and decoupling.