This apartment is awesome. The area is incredible, 2min from Piazza Navona and Pantheon, 2min from the bridge to Castle of St Angelo, 10min walk from St Peter's Square Vatican, 10-12min walk from the Roman Forum and 15min from Colloseum, 5min walk from Spanish Square, 3min walk from Piazza del Popolo and the Villa Borghese park. I spent 5 nights in this apartment. It's really big and nice. Big living room with a TV, 2 comfortable Sofas, more comfortable chairs, very comfortable nice big bed in the bedroom, kitchen and bathroom are fine too. 3 or 4 big nice windows if you close them you have quiet, if you keep them open you can feel the athmosphere from the Roman streets. My guess is you could easily stay 3-4 people in this apartment, it's got plenty enough room for that, see with the owner for his conditions if you need to be that many.

Using Google, I found 2 awesome restaurants just next door. Ristorante La Campana is my absolute favorite, it feels very authentic and not touristy, I tried the Tonnarelli Cacio e Pepe Pasta, perhaps the best pasta I ever tasted, the Saltimbocca alla Romana con funghi is also totally amazing and awesome. The other really nice restaurant is Da Gino just 1min walk further "to the left" next to the parliament square. Plenty of cool Ice Cream Gelatti places just down the street, Il Gelo has great chocolate and vanilla/cream taste.

I spent my 5 days going to the Capitoline Museums, The National Museum (next to Termini station), Roman Forum (5€ guided tour recommended), Colosseum (8€ guided tour on 3rd floor and underground recommended), Vatican Museum by night with classical concert (Fridays, some months), watching AS Roma or Lazio play in the Olympic Stadium is really nice too.