Novice Digital (wired) Question(s)

I just acquired a tube integrated which only has RCA inputs.  I’ve ripped my entire CD collection to iTunes on my Mac which resides in a work space several rooms away from this amp.

1.  What sort of (USB?, other??) wire on one end to left & right RCA cable on the other end would I need to route, in wall/ceiling, from Mac to integrated amp to achieve the same sound quality from these ripped files as what I previously experienced with a stand alone CD player ?  (My Denon DCD-1560 player, from the mid ‘80s has bitten the dust.)

2.  Would the use of some sort of go-between device (line amp/DAC/etc.) be necessary to achieve this?

I ‘d be controlling iTunes on the Mac via the “Remote” app on my iPhone.

The first thing you need is a DAC. There are many out there anywhere from $100 to thousands of dollars. I would go with a reasonably priced one from one of the better known manufacturers to start with. You can always upgrade later if you feel the need. The next thing is getting your ripped CD files to the DAC. I would recommend going wireless and use Apple Airplay because you already have a Mac and are using iTunes and your Mac is several rooms away.  If you use Airplay all you need is a 2nd Gen Apple Airport Express or 3rd Generation Apple TV to receive the signal and export it to the DAC. You can do this with an optical cable or coaxial cable. I have been using airplay for my lossless ripped files to an Apple TV or Airport Express for over 8 years in 4 different systems in different rooms and have never had a dropout or any issue. It always works flawlessly.
Going the Apple Airplay route, would you anticipate any appreciable loss in sound quality as opposed to via a cable?  Actually, I’ve been using an Apple TV to more or less do this thru an AV receiver prior to getting the tube amp.  Trouble (?) is that, due to limited inputs on my PrimaLuna Prologue Classic, all such video sources are routed thru the TV, which functions as a switchbox (degradation of signal?). However,... I just happen to have an unused Airport Express lying around.   I guess the only missing link is the DAC then?  One other concern — I’ve digitized a ton of vinyl via Audacity in the form of 16 bit AIFF.  Would this present a problem for a lot of DACs?  Thanks again!
I haven't noticed any loss in sound quality going wireless.

I incorrectly mentioned using a coaxial cable for the output of the Apple TV and Airport Express. I was thinking of something else when I typed that. They do not have coaxial outputs.
I've used the optical output from an iMac, Apple TV3 and Express to systems in my living room, office and garage. The primary limitation on sound quality in the last two isn't Airplay, it's the high level of jitter inherent in the output from the Apple devices. That doesn't mean you can't enjoy the music, I certainly did in all those systems, but if you want better fidelity reducing the jitter is the place to start. 
There are at least a couple of ways to do that, get a DAC (almost certainly a more expensive one) that does a better job of reducing the jitter itself or put a reclocker between the optical output and the DAC.
The Wyred4Sound Remedy Reclocker did a great job in my office system between an iMac and a Simaudio D100 DAC. It made less difference in the living room into a Simaudio D300, a considerably more expensive piece that handled the jitter better on its own. 
In the living room I eliminated the Apple TV as an audio source and now use instead an Arcam rPlay. The Airplay signal goes from my iMac to an 
Apple Extreme router and then via Ethernet to a Wyred4Sound DAC 1. That made for a substantial improvement.
All this to say that I think your effort should be focused downstream of the Airplay signal.
Thanks very much, sfar.  Sounds like a great system....not sure if I’ve got the finances to go that route though.  

I think I’ve got the info narrowed down enough now, re: my own circumstances, to ask a more focused question that’ll help me to decide whether bring digital playback onboard my setup or to stick with it being primarily for vinyl — If I stream music from the iTunes in my Mac via an Airport Express into a modestly priced DAC, (a basic model Cambridge DACmagic or a Schiit Modi 3) and into my system’s integrated amp, can I reasonably expect sound quality as good or better than was the case before this music was ripped into my Mac and was being played as compact discs on a mid-1980s CD player which cost approx. $750 when new?
Jitter may or may not be an issue for you depending on the DAC you use. For me it was a non issue, even with an inexpensive $200 DAC. I read so much about jitter and wondered if it was present in my wireless systems using an Airport Express or Apple TV, even though they sounded fantastic and as good or better than my CD players (an OPPO, an older Denon, and an older Sony). Just to see if I could improve the sound I tried an IFI S/PDIF iPurifier and it actually degraded the sound making it somewhat muddled. I also tried the Wyred4Sound Remedy Reclocker and I could not tell a difference.

I would caution you that there have been reports that some people had problems using the Cambridge Audio DacMagic with an Airport Express.
Thanks for the info, ljgerens,...It’s been most helpful to me in making this process understandable!

Finally got some spare time to do some more web surfing on the topic and, based on what I’d read, decided to go ahead and hook up the Airport Express to the PrimaLuna’s CD input and stream from my Mac’s iTunes without a DAC other than the internal one in the AE.  The Prologue Classic is pretty much old school basic insofar as it only has RCA inputs so the Apple Express is connected via the (3,5mm?) stereo pin into right/left RCA.  Early impressions, after streaming Paul Simon’s “Graceland” (ripped to iTunes from my CD) using the “Remote” app on my iPhone are...well...I’m smiling.  At some times I’m thinking it sounds better than my old Denon DCD 1560 CD player...other times it sounds about the same to me.  Interestingly, I’m finding I have to turn the volume control on the PrimaLuna to about “10:30” with this digital file to attain the same sound pressure most of my LPs create thru this setup (Music Hall MMF-5/stock Goldring cart > Music Hall PA1.2 stage > integrated amp) at 10:00 o’Clock.  It’s always been that digital sources were inherently louder than vinyl...sometimes much so...before this.  I’ve checked to make sure all volume settings sliders on the Mac and iPhone are maxed out so I guess this is just a different order to things.  All in all, extremely pleased!  I’ll probably just continue to enjoy the ‘tunes this way until a “no obligation” type scenario presents itself with regard to trying out an external DAC, if ever.  Truth be told, I still like my vinyl best with this rig but I sure would’ve missed out on a lot had I kept digital streaming relegated to my one-step-above-boombox, workshop system!  Anyway, thought someone might be able to glean some useful info from my experiences here.  Thanks again!
Glad it is working out for you. The internal DAC in the Airport Express is pretty good, probably equal to the built-in DACs in many receivers, integrated amps, and CD players. It sure makes it convenient to listen to your favorite music. 
Glad you got it set up. I'll admit that I don't know if I know what jitter sounds like but when I stream via Apple TV>optical>DAC the sound quality is not as good as when I stream (or play ripped CD) directly from computer> USB>DAC. It isn't a huge difference but it is there.

So I use an old iMac to play ripped CDs in iTunes through USB to DAC and I'm satisfied with that.

Will consider upgrading from $150 DAC in the future.