I noticed that there is already a very acurate tab of this song on this site,
But I thought it would be fun to aproach this song in a different way.

Here's the bulk of it...
  |A5              F5              |C5              G5              |
G||9———————x—x—x—x—5———————x—x—x—x—|12——————x—x—x—x—7———————x—x—x—x—||
D|o7———————x—x—x—x—3———————x—x—x—x—|10——————x—x—x—x—5———————x—x—x—x—o|
A|o————————————————————————————————|————————————————————————————————o|
E||————————————————————————————————|————————————————————————————————||
  |1 e + a 2 e + a 3 e + a 4 e + a |1 e + a 2 e + a 3 e + a 4 e + a |

aside from the cool fills that he deos in certain parts,
this is pretty much the entire song.

What we're going to do is break down the chords and key of the song.
then we're going to check out all the stuff we can do over the changes.

although power chords don't have a third in the chord,
(the interval that defines if a chord is major or minor.)
the changes (and the melody) imply that the song is in C major (or A minor)

This means that if you were to play a fill, 
any note in C major would work.

Here is the C major scale in 2 octaves...
 |C  D  E  F  G  A  B  C  D  E  F  G  A  B  C  |
G|————————————————————————————————————14—16—17—|
D|————————————————————————12—14—15—17——————————|
A|————————————10—12—14—15——————————————————————|
E|8——10—12—13——————————————————————————————————|

Being able to play this in 2 octaves gives you a wider range.
it also gives you a better understanding of where the notes are.
*there are other places on the neck where these notes exist*

lets use a  random example:
  |A5              F5              |C5              G5              |
  |                                |                G D C B G A B   |
G||9———————x—x—x—x—5———————x—x—x—x—|12——————x—x—x—x———7p5p4—————————||
D|o7———————x—x—x—x—3———————x—x—x—x—|10——————x—x—x—x—5———————5h7/9———o|
A|o————————————————————————————————|————————————————————————————————o|
E||————————————————————————————————|————————————————————————————————||
  |1 e + a 2 e + a 3 e + a 4 e + a |1 e + a 2 e + a 3 e + a 4 e + a |

all the notes in the fill over the G5 are in the key of C major.
There are soooooooooo many variations of this.
explore!

another way to approach this is to think of the chords.

In diatonic harmony, (a song in one key/scale)
each note in the scale becomes a chord in the key.
this is the number and quality of each chord in any major key:
(our example is C major)

1) major (1 3 5)       ex) C major (C E G)
2) minor (1 b3 5)      ex) D minor (D F A)
3) minor (1 b3 5)      ex) E minor (E G B)
4) major (1 3 5)       ex) F major (F A C)
5) major (1 3 5)       ex) G major (G B D)
6) minor (1 b3 5)      ex) A minor (A C E)
7) diminished (1 b3 b5) ex) B diminished (B D F)

with this knowledge, let's take the chords in this song,
(A5,F5,C5,G5)
and give them qualities

in C major: 
A5 = 6) = A minor (A C E = 1 b3 5)
F5 = 4) = F major (F A C = 1 3 5)
C5 = 1) = C major (C E G = 1 3 5)
G5 = 5) = G major (G B D = 1 3 5)

now let's stretch it out:

 |A minor in 2 octaves |F major in 2 octaves |
 |A  C  E  A  C  E  A  |F  A  C  F  A  C  F  |  
G|——————————————————14—|——————————————————10—|
D|————————————10—14————|————————————7——10————|
A|——————7——12——————————|——————3——8———————————|
E|5——8—————————————————|1——5—————————————————|

 |C major in 2 octaves |G major in 2 octaves |
 |C  E  G  C  E  G  C  |G  B  D  G  B  D  G  |  
G|——————————————————17—|——————————————————12—|
D|————————————14—17————|————————————9——12————|
A|——————10—15——————————|——————5——10——————————|
E|8——12————————————————|3——7—————————————————|

Playing these chord tones in two octaves is great for opening up the bass.
*Keep in mind that there are other places where these notes exist*

lets use a random example:
  |A5              F5              |C5              G5              |
  |                                |                B D B G D B     |
G||9———————x—x—x—x—5———————x—x—x—x—|12——————x—x—x—x—4h7p4———————————||
D|o7———————x—x—x—x—3———————x—x—x—x—|10——————x—x—x—x———————5—————————o|
A|o————————————————————————————————|————————————————————————5/2—————o|
E||————————————————————————————————|————————————————————————————————||
  |1 e + a 2 e + a 3 e + a 4 e + a |1 e + a 2 e + a 3 e + a 4 e + a |

all the notes in the fill over the G5 are notes in a G major chord.
explore!

Another Great trick is to use pentatonic scales:

Minor Pentatonic = 1 b3 4 5 b7 
Major Pentatonic = 1 2 3 5 6 

Let's apply these over the chords:

 |A minor pentatonic in 2 octaves  |F major pentatonic in 2 octaves  |
 |A  C  D  E  G  A  C  D  E  G  A  |F  G  A  C  D  F  G  A  C  D  F  |
 |1 b3  4  5 b7  1 b3  4  5 b7 1   |1  2  3  5  6  1  2  3  5  6  1  |  
G|———————————————————————————12—14—|————————————————————————5——7——10—|
D|——————————————————10—12—14———————|———————————————3——5——7———————————|
A|—————————7——10—12————————————————|—————————3——5————————————————————|
E|5——8——10—————————————————————————|1——3——5——————————————————————————|

 |C major pentatonic in 2 octaves  |G major pentatonic in 2 octaves  |
 |C  D  E  G  A  C  D  E  G  A  C  |G  A  B  D  E  G  A  B  D  E  G  |
 |1  2  3  5  6  1  2  3  5  6  1  |1  2  3  5  6  1  2  3  5  6  1  |
G|————————————————————————12—14—17—|————————————————————————7——9——12—|
D|———————————————10—12—14——————————|———————————————5——7——9———————————|
A|—————————10—12———————————————————|—————————5——7————————————————————|
E|8——10—12—————————————————————————|3——5——7——————————————————————————|

*Keep in mind that there are other places where these notes exist*

lets use a random example:

  |A5              F5              |C5              G5              |
  |                                |G A C D E G                     |
G||9———————x—x—x—x—5———————x—x—x———|——————————12————7———————x—x—x—x—||
D|o7———————x—x—x—x—3———————x—x—x———|————101214——————5———————x—x—x—x—o|
A|o————————————————————————————————|1012—h——/———————————————————————o|
E||————————————————————————————————|——h—————————————————————————————||
  |1 e + a 2 e + a 3 e + a 4 e + a |1 e + a 2 e + a 3 e + a 4 e + a |

All the notes in the fill over the C5 are notes in a C major pentatonic scale.

Notice how i'm adding Hammer—ons, Pull offs and slides.
experiment with these!
they'll give your ideas more life!

You're gonna want to use all of this information with responsibility. 
It's very easy to go over board with all of this stuff.
However, This is a great tune to use these concepts over because the song...
is only 4 chords the entire time.

If you're wondering about how to approach this stuff rhythmically,
it comes down to one thing...
what are the drums doing? 
the most important question any bass player must ask themselves!
listen to what Chad is doing on the recording and try to respond to it.

The best part about all this stuff is that you can apply this over any song.
i hope you enjoy!

—Connor Larkin