I decided to try recording a strictly ambient guitar piece, and ended up creating something else entirely.
First I recorded a series of simple one-note volume swells ... funny fact about these notes - I used PI (π) as my tab - i.e., 3.141592653589793 - using the low E string, I played the notes at the 3rd fret (G), 1st fret (F), 4th fret (G#), 1st fret again, 5th fret (A), and so on.
I used a compressor to keep the note nice and sustained, and I used my Morley Mini volume pedal to swell the notes in. My clean tone was my Tech21 FlyRig5 CALI, only using the Samsamp section for the first half, then I added the CALI drive section for the second half.
Then I added a boatload of effects after recording - some EQ, chorus, phasing, some pitch-shifting, and some delay and a LOT of reverb. A LOT of reverb, to really sustain the notes for a long time.
This is how I created "Ambient Only".
But after completing the piece, I wanted to completely turn it into something else. Luckily, I thought ahead a bit when I recorded the "swells", because I recorded them with a "click track" on. So now I can add some additional instruments, including MIDI instruments since everything will sync to the tempo.
So I added some drums using EZ Drummer, then added the "solo" guitar (following the notes so I could figure out what key each section is in), then added live bass (my trusty old Squier Affinity P-Bass). Voila - the piece called "An Ambient Jam."