Muxu isn’t a bad place for a few days, has showers and a small cafe, couple of supermarkets close by and a 10-15 min walk into Saint Feliu de Llobregat town for shops/eating and train into Barcelona.
Parking is secure, 24hr security and staff are friendly. 15 euro for 24hrs.
Worth emailing them in advance to book a space as it fills up quick though.
A lot of the drivers tipping Barcelona with a few days to kill before load out head down to El Buffet at Altafulla, decent truck stop but about an hours drive from Barcelona.