Casa Di Penelope is very closed to everywhere, you can stay safely,
fontana di trevi is just one station with metro, you can go to spanish steps with metro from the hotel, piazza di venezia is just 3 station with bus,
it's easier to prefer bus in termini, you need roma pass for bus but our roma pass doesn't work on it (noobody realized and warned so we traveled without ticket, our roma pass was useless for us), after 12 pm there isn't any bus or metro so you should take taxi, taxi costs max 15 euro around the city,
you can take citysightseeing tour ticket (20 euro for 2 days) , it's the easiest way for a cultural tour
find Mr.Babu in Penelope, he's very helpful and we were completely happy from the hotel..
Hotel was clean, safe, pretty, silent, comfortable...
