no, you go to monteriggioni, Rome, Florence (Cristina memories) and a few other places like Leonardo missions take you out of Rome im pretty sure, and sequence 9 you go to another country, but thats it, you cant go everywhere u went in 2
By singleplayer do you mean campaign mode? You're able to go to all of the places you could in the second game depending on what sequence you're playing through. There's a total of 9 sequences with a ton of back and forth.
Ive just played threw it and finished it, And almost all sequences. Ive killed lucy (The accidental thing) and then they put me back in animus and you cant get out. How do you go anywere else?