Richard, I am unaware of any trolley in this city, unless it is the tourist bus .... (Can't opine on which bus tours are best; there are several.)
Limiting myself to the core of downtown/gulch/germantown, for restaurants: Otaku Ramen is a great budget friendly place, as is Little Octopus, which is in process of moving to the gulch from East Nashville; Pinewood Social, City House, and Rolf and Daughters are less friendly on the wallet, but get a lot of deserved accolades. (City House is one of the true bargains if you want to dine with a James Beard regional winning chef.) Bastion (make reservations in advance--20 seat restaurant), Etch, Prima, and Husk are very good, but getting into expensive territory. Catbird Seat is a must if you can make your reservations online 30 days in advance at midnight--and are willing to pay very expensive tab (for Nashville--450 for two with alcohol pairing, tip, and tax).
If into history, Andrew Jackson's estate, the Hermitage, is about 10-13 minutes from airport, just east of Downtown.
As for downtown hotels, I think they are pretty much as expected, although priced a bit high. The Doubletree has been spending a lot of money on upgrades--but don't know if that puts them ahead of others, or merely catches them up!
E.T.A.: Regarding live music, DW and I have been pleasantly surprised to find that inexpensive live music is easy to find outside of the Country and Bluegrass genres.
