If you want to blaze around the bass fretboard like there's no tomorrow then there's no way around it: you're going to have to memorise the neck really well.
This is an amazing method that will get you playing scales, triads, and arpeggios in three different ways. It's amazing how something so simple can lead to huge results...
Scroll down for related lessons and the free PDF for the lesson.
The Basic Idea
Here's an example from the lesson using A Mixolydian. Watch this lesson for more on modes.
Starting with the second finger:
This is quite a compact little shape.
Starting with the pinkie finger:
Notice how the scale notes are the same but this time they are heading to the 2nd fret.
Starting with the first finger:
This one really opens things up.
Be able to map out all of these shapes onto the fretboard and shift seamlessly between them. Hand shifts, slides, extended fingering, and great coordination between the hands will make it much easier.
Add this into your practice routine until you master it then transfer it to other scales and keys!