The train ride was mentioned but it really depends on when. I was a member of the museum and we had rides included in our membership tier. It only operates on weekends in summer and on certain holidays.
https://www.californiarailroad.museum/visit/excursion-train-rides
Old Sacramento is kind of cheesy but that's kind of good, clean tourist fun sometimes. One thing you might consider is a horse drawn carriage ride, although I'm not sure when they run those other than weekends/holidays during summer. I took my kid on those rides, and the prices for all rides are required to be fixed. Just around a few blocks was $10 when I rode on it, although they also take tips. There are more expensive trips including ones to the State Capitol Building. Looks like it's $20 now for the short ride.
https://www.oldsacramento.com/attraction/carriage-rideshttps://www.tophandranch.com/services-pricing.html
The irony is that Sacramento Chinatown is across the street from the Sacramento Valley Station, but there's hardly anything there now worth visiting. It was turned into kind of a sterile mall in the 1970s and it completely lost any character. There's barely any retail businesses left - I think maybe one Thai restaurant now. It was a thriving Chinatown for over 100 years but it's kind of sad what redevelopment did to it.
http://www.valcomnews.com/sacramento’s-chinatown-fell-to-revitalization-project-in-the-1960s/
There's been some redevelopment of the downtown area in the past few years - especially with the new Golden 1 Center, which is the home of the Sacramento Kings. You might check the schedule to see if there's a game or perhaps a concert. I'm looking at the schedule for the next few months and it's mostly NBA games, but also concerts, a monster truck show, a rodeo, Mexican bands, Disney on Ice, Justin Bieber, Billie Eilish, Celine Dion, etc. If it's summer then there's New Kids on the Block (how old are they?) on June 2 and Shawn Mendes on June 30. It's still early and there aren't any NBA games in the summer unless the Kings inexplicably make the playoffs.
https://www.golden1center.com/events
This is making me feel old.
The old Downtown Plaza shopping center still partially exists (as Downtown Commons) even though part of it was torn down for Golden 1 Center. You could kill time by watching a movie and there's still Macy's and restaurants. I haven't been to that specific location, but I do like the Yard House restaurant chain.
https://www.docosacramento.com