PRE-arrival day
I would suggest that you purchase a city guide book of Rome which will provide excellent information for the area near the Gran Melia. You will find many places within walking distance such as the Campo D'Fiori and great restaurants in and around the area. I wish I could remember the name of the pre-arrival day restaurant where we ate dinner, but unfortunately we did not document it. We had 9 family members all at an outside table. The staff took all our individual orders but then brought everything out "family style". It was a delightful experience! This included a special treat when a street musician stopped at our table with his accordian.
The Rome
ABD tour will show you the famous Via Condotti which is straight in front of the Spanish Steps but will not stop for shopping. Please go in to some of the shops! Prada has excellent items both large $$$$ and moderately large $$ (belts, coin purses, key chains, etc.) I purchased our daughter a small Prada shoulder bag in 2008. The purchases for handbags are made in private upstairs down a hallway where the handbag, etc. is registered and properly bagged with official duty free paperwork provided. The official tour does not have enough time to do these things.
Don't miss the nighttime in Piazza Navona!
POST-departure day
Your last ABD night in Venice will be so remarkable that your post-night may be a little letdown; however, make sure you jot down places you wish to re-visit. I would not re-visit the major attractions since this is your main opportunity to experience locals. Remember the sestiere (district) in which you may have entered; there are 6 of them and one can be lost since you no longer have a tourguide.
A good idea is to have a city map or use your phone. On our first trip we were at the Grand Hotel Dei Dogi in the Cannaregio district. On our post-night my DH and I had dinner at Vesuvio's Ristorante (no longer open-?pandemic). It was the ideal place to eat and watch the Venetians come out of their houses for the evening stroll and socializing hours. This is a long-time ritual (la passeggiata) that we enjoyed and should not be missed.