Thadius856, the longest run in my house is 28 feet, and have had no problems with gig speed on cat-5e. We have had no problems watching HD on our Roku through wifi, nor transferring files through wifi to the computer that is wired to the RG (3800HGV-B) for ATT U-Verse. Very seldom do we transfer, but we do watch a lot of Netflix, and never have had a glitch.
The best thing the OP can do, is sit down and draw out a plan of where the current telephone & catv connections are, and figure out how many connections are needed. As for the NID, you need to leave as is. Best thing is to pull all wires (catv, telephone, networking, audio, lighting controls) into a central point such as a laundry room, or utility space (ie basement), then pull the runs from there.