ROME — On a steamy evening in late June, Lisa Scen, a retired cook of inscrutable age, donned a simple beige dress and glittery earrings and prepared to go to her first night at the opera.

Actually, the opera came to her.

The OperaCamion, a mobile stage, with its cast and crew, set up in a shabby square of scorched, uncut grass in the outlying San Basilio quarter of Rome, where Ms. Scen has lived for the past 30 years. It was a free, one-night performance of Mozart’s “Don Giovanni.”

She was excited.

“Rich or poor, we all need diversions, especially in summer when it’s so hot,” said Ms. Scen, scouting for a seat and zeroing in on one of the few benches in the square whose wooden boards had survived past acts of vandalism. “The difference is that the rich can go on holiday, and those who can’t are destined to solitude.”

That made the evening’s entertainment — provided by a young cast of singers and Teatro dell’Opera di Roma’s youth orchestra — all the more special, “like going to a wedding,” she said happily.