Well first I would not be playing modes. Modes are melody notes and I play chord tones or notes of the chord. So here is what I would do.
I first find the chord progression on the song by asking Google for: Guitar chords, Sweet Home Alabama -- and got this.
http://tabs.ultimate-guitar.com/l/lynyrd_skynyrd/sweet_home_alabama_crd.htm
OK now that I have the chords I next want to know the key. Why? So I can place the root note of my Major Scale Box Pattern over the note found on my fretboard.
Code:
Bass Patterns based upon the Major Scale box.
Major Scale Box.
G|---2---|-------|---3---|---4---| 1st string
D|---6---|-------|---7---|---8---|
A|---3---|---4---|-------|---5---|
E|-------|---R---|-------|---2---|4th string
Want to build a bass line around the Cmaj7 chord? Place
The R in the box over a C note on your fretboard. The one
at the 4th string 8th fret is what I would use. Then play
the R-3-5-7 found within the box. Those are the notes of
the Cmaj7 chord.
Next thing I would do is decide what key is being used in that fake chord sheet music. Notice how all the verse lines end with the G chord. That tells me that this song is to be played in the key of G. Key of G major chords are; G, C & D or D7. It is here that I use the Nashville number system and on the fake chord I substitute Nashville numbers for chord names, i.e. ......
Key of G has these chords: G, Am, Bm, C, D, Em, F#m7b5
Nashville numbers for that..1..2.....3.....4..5..6.....7
I put a 1 over the G chord notation on the fake chord, and yes a 4 over the C's and a 5 over the D's. Then I place my major scale box so it will have the notes of the key of G in them. Forth string 10th fret and then play from the fake chord.
Lyric syllable - one note per syllable. Big wheels keep on turn-ing. OK Big gets one note and I'm going to play just roots for now - so D chord is what Nashville number? Yep, it's a 5. So in my box I grab a 5 for one beat. Now up comes the C chord over the lyric word "wheels" so I sound the C chord or 4 on my box. Now the lyric words "keep on" each need a beat of the 4 and then the word "turn-ing" is going to need a G chord and that is the 1 Nashville number, so I sound the 1 in my box twice, why twice? because "turn-ing" has two syllables.
That's it. Keep going with all the verses of the fake chord.
Gotta go, will check back later.