Maybe at this point you could tell us what it is your going to be doing, recording full bands? 

Recording only live instruments and live vocals - mainly acoustic and Irish traditional - no midi.
 
Just say I was starting from scratch with only Sonar Producer 8.5, a few mics, D.I. boxes and a Presonus Audiobox. What are my best options for setting up with that gear - to avoid using the virtual faders on screen? Someone mentioned a 'snake' - what is this and where does it fit in the chain of things? My priority is physical faders over 16+ channels. Thanks again!  :)

Well that's still not telling much, Studio recording? Live? just you? or how many people playing at once? 
 
The Audiobox can record 8 tracks live, it can also be controlled remotely with an iPad. 
You would use a snake if your musicians are in one room and you another, A snake is just a cable extension,  but because of the wireless remote I don't think this would be necessary. 
 
For live recording you set your levels and for the most part hit record and that's it. Your not mixing while recording, That will happen back in the studio. Controllers are a nice option but I use track automation so find there's no need for using faders during mixing anymore. 
 
FYI you cannot use 2 ASIO audio interfaces , but it might work if you can use WDM driver mode. 

Cactus Music
Well that's still not telling much, Studio recording? Live? just you? or how many people playing at once? 
 

Sorry but I'm not informed enough to be able to use language that experienced sound recording engineers use freely!
 
Studio recording? Yes
Live? Not on location but yes, all real instruments.
Just me? No, not at all. Duos, trios, 4, 5, 6-piece acoustic groups, e.g: folk, trad, bluegrass, etc.

Ok that helps a lot. You see it's different equipment needed for different situation. You can record in a studio set up and "get by" with only 8 channels. What you are planning ( building a small studio) will need a lot of planing and careful study of how this is done. Asking on a forum is not a recommended way to learn about this as you will not be getting 100% foolproof advice. 
I would look for a book myself, that's how I got started. Then read magazines like SOS. 
Lots of article on the net. 
 
The reason I say this is there is no one way approch to recording groups of musicains. It can run anywhere from using one mike to using 24+