Questions about: planning

I have a project to run around 40 lan cables in loft style office. The office don't have any conduit attached to ceiling at all. The location of RJ45 Jacks is multiple
I am remodeling my entry way and dining room to give a more open feel. Existing: 15 Amp breaker 12-2 Feed directly from the box two gang box outside of the kitchen 1 standard switch and 1 three way (chandalier turns on and off from entry and kitchen