Don't forget The Spudnut Shoppe in Uptown Richland (south side ). Great potato based doughnuts. cinamon rolls. and maple bars.
Definitely go for some Mexican food in Pasco. There's a taqueria in what used to be the Tastee Freeze near Pasco High that is excellent. The menu is in Spanish, and they'll call your order number out in Spanish, so make sure you know some basics of the language. Taco trucks are also usually a good bet.
The Pasco farmer's market is also great, but I don't know if it's open this time of year.
Okay, I grew up in Tri-Cites and if memory serves me correctly, the restaurant scene was for the most part filled with chains. Most of the good independents were quick to fold, very sad. So I will take a stab at this for ya, hopefully these places are still open and still good.
Apollo's Greek Restaurant: My dad's favorite. Decent Greek food, great people. The atmosphere is a little cheesy, but the food was always good. Had my first gyros here.
TS Cattle Company: Another family favorite. Steaks were always cut well and cooked perfectly. Live music was always a plus. Good place for out of towners.
Rattlesnake Mtn. Brewing Co.: Food was consistent. Portioned well. Not spectacular but a great standby.
Monterosso's Italian Restaurant: More genuine Italian than Olive Garden, space is a little cramped but service was always excellent.
Casa Mia: A chain, I know but the have the best pizza in the world. You have to try their potato gorgonzola and truffle pizza, yum!
Taco Trucks: Yep, they all pretty much rock, more authentic than any restaurant.
Green Gage Plum: A little whole in the wall with fantastic food!
I second the spudnut too. There are so many restaurants that I miss that are long gone like Blackberry's, the Sunfire grill, (ironically had the same space), Che Chaz, and a few others. I am interested to know about the new gigs like Bin No. 20 and Bonefish Grill. Any opinions?