Since the melody is more like a solo, the accompaniment must follow the flow of the melody both with its slow build and quick decline as well as any tempo liberties that are taken for expressive purposes. We need to think of it as a living, breathing musical being and not like a performance in a box.
String crossings and slurred arpeggios in the accompaniment are also a reoccurring feature of this piece. For lower strings, getting the bottom pitches to sound can be tricky. When the string is still, it takes more effort to start it vibrating. One trick I've used in situations like this is a small "hammer strike" with my left hand finger. This gets the string to start vibrating before the bow tries to start the string, and can allow for smoother articulation in the bow with more speed to project the sound without the tone becoming crunchy or wispy.
Some other good examples of similar style are Hofeldt's pieces In the Company of Angels, and Lullaby.