All of Hamlet takes place in Denmark. Rome is in Italy. Therefore nothing happens in Rome in the play.
Horatio refers to the murder of Julius Caesar in the following lines in 1,1:
Horatio: A mote it is to trouble the mind's eye.
In the most high and palmy state of Rome,
A little ere the mightiest Julius fell,
The graves stood tenantless and the sheeted dead
Did squeak and gibber in the Roman streets . . .
The murder is only referred to in Hamlet but is portrayed in Shakespeare's play Julius Caesar.
Hamlet - questioning the meaning of life
act 3 scene 1 lines 147-148 :)
no
Horatio plans to go meet Hamlet at Elsinore, which he does in Act 1 Scene 2. Horatio plans to meet Hamlet on the battlements, which he does in Act I Scene 4. Horatio plans to meet Hamlet at the play, and does in Act 3 Scene 2. Horatio has no plans to meet Hamlet in England.
I believe that he is speaking about Hamlet Senior and his recent death, that it is fresh.
Hamlet - questioning the meaning of life
There is Hamlet's father, of course, The Ghost. There is Laertes's and Ophelia's father, obviously. We hear in Act 1 Scene 1 about Fortinbras's father who was killed by Hamlet's father And there is Priam in the Player's speech: "But with the whiff and wind of his fell sword, the unnerved father falls."
Hamlet, Act 3, Scene 1.
The Ghost, in Hamlet, Act 1 Scene 5
In the exposition of Act 1 Scene 5 in Hamlet, two characters speak: the ghost of King Hamlet and Prince Hamlet. The ghost reveals the circumstances of his death to Hamlet, setting the tone for the rest of the play.
act 3 scene 1 lines 147-148 :)
no
In Act 1 Scene 4
Hamlet. See http://www.opensourceshakespeare.org/views/plays/play_view.php?WorkID=hamlet&Act=1&Scene=1&Scope=scene
These are the first six words of a speech Hamlet makes in Act 3 Scene 1 of the play.
She's the same person she is in the other four acts of the play--Hamlet's mother.
Horatio plans to go meet Hamlet at Elsinore, which he does in Act 1 Scene 2. Horatio plans to meet Hamlet on the battlements, which he does in Act I Scene 4. Horatio plans to meet Hamlet at the play, and does in Act 3 Scene 2. Horatio has no plans to meet Hamlet in England.