Hi,
@Multipurpose.
Yes, I went by there in 2015.
It wasn't intentional, and was a bizarre surprise.
I'd suggest you forget the taxi! It's gorgeous walking!!!
To get there, take the afternoon bus to Santo Domingo de Silos from Burgos. Spend the night and in the morning walk out of SDdS on the
GR82 (NOT the Camino del Cid or the Ruta de Ebro). You'll walk steadily uphill on a dirt road, and when it reaches the top of the ridge it drops down to the right into the next valley over. Just keep following the road towards Contreras and the Sad Hill Cemetery will be on your right. It's marked. I can't quite remember, but maybe it's an hour and a half or two hours one way? With views to die for at the top of the hill....
You could take the evening bus back to Burgos or spend another night in SDdS, which is what I would probably do. It's a very nice place, and the evening service with Gregorian chant at the monastery is very special.
Or...
...you could walk to Covarrubbias on the Ebro and then back to Burgos via the Camino San Olav. It's 3 days of 5-star walking!!
Edit - the light colored road that turns up to the top left of the satellite pic that
@Peregrinopaul posted is the GR82.