Rome in 4 days - the good location hostel, places to go while traveling alone?

Yes, central Rome is actually very safe for a big European city so you will be fine traveling alone (in case you were worried) my wife and I have only ever felt safe walking through Rome at night.

This top 10 free Rome tourist attractions will give you a good starting point http://www.romanlife-romeitaly.com/rome-tourist-at...

You will also find info about the Pantheon and Roman Colosseum just below.

For some help and info about the Rome public transport system http://www.romanlife-romeitaly.com/public-transpor... should be an valuable source.

For hostels, hotels, B&B's I use hotelsCombined http://www.romanlife-romeitaly.com/central-rome-ho...

to compare prices from several online hotel booking companies - this greatly increases my chance of getting the best rates for accommodation in Rome Italy.

If you are unsure about which area of Central Rome you would like to book your accommodation you can see http://www.romanlife-romeitaly.com/rome-italy-map.... for some advice and maps of the central Rome areas.

Enjoy!

Absolutely: first of all San Pietro and the Dome (cupola) where you can see the Roma panorama... Colosseo, Fori Imperiali, Piazza Venezia, Fontana di Trevi, ecc. ecc.