Whether you arrive from Ciampino(Terravisionbus) or Fiumicino (Leonardo Da Vinci express) airport- hotel is very easy to find. Out right from Termini- up via Marghera. At end you look right and see the big yellow building- very easy to find. Yes there is a main way to cross to get there- in Rome drivers do not know what these white lines are, so you just need to go and they have to stop. Thats the way in Roma.
Arriving through the gate turn left and you will find reception desk. I was greeted by smiling and very helpful staff - did feel very welcome at all times. The tv-thingy was a bit difficult for me to find out, staff came to my room and helped me. My room (301) was on the 3rd floor in the next building (big single or small double), clean, big bathroom, small showercabin, a tiny balcony with view to the yard. A good standard room for Roma. Aircon did work perfectly.
Notes on Serendipity:
1) There are few rooms next to the reception area (ground floor), the rest is situated in neigbour building on the 3rd floor.
2) Elevators are tiny (very common in European cities)- and you need to remember to close all doors in order for the next arriving guests to use it!!!! It is noted in the cabin it self in several languages.
3) The rooms does not have phones- so if you need help or need to contact the staff, you need to go down by elevator/stairs and find the reception.
4) Breakfast is not served at the residence itself- you need to go out and cross the busy street in order to get your coffee. I did not try it- so can not comment on standards.
5) When situated near a main trainstation you meet all kinds of people- a few homeless people etc. Would not consider this area as seedy. No worries.
6) as you probably know, Rome is incredibly expensive- if you need to buy water etc. Get out at Termini, turn right and you will find a SPAR-supermarket (Called DeSpar in Italy).
7)Termini Station- here you find many thing in food, newspapers, shopping and transportation to airports. Just in front of maindoors you will find busses, Metro and sightseeing coaches.
I do recommend The Serendipity Residence for its great location, decent rooms and rates. For a Huge city inwaded by tourists everyday- I think service was good and friendly.
Would you like the city- i have no idea, either you do or dont- but rome is Rome and you need to see it at least 1 time in your life:-)