Earth orbits the Sun at an average distance of 149.60 million km [WP]
45 degree angle (see Quora animation): 150000000 * cos(45) = 79000000
Earth projection sits between Voyager and Sun.
"...travelling at around 61,500km/h ": 79000000/61500/24 = 53 days to add the equivalent of that distance in LD time.
Edit: huh, since Earth sits between voyager and the Sun, the LD distance is satisfied for the Sun first.