Internship as in medical? If she is at Kaiser? If that is the case then Hacienda Grill is the best option. It is nearest and actually one of the better full scale Mexican restaurants in Richmond.
A few blocks away is Mi Pueblo Taqueria and Meat Market
The place looks dicey, but on the weekends there is a grill outside with carne asada and chicken out front. In the back is a nice little restaurant.
If she does work weekends I can give you a whole different set of recs as the tamale vendors come out and some restaurants do different dishes.
Does she have a car? With that BART station right there if she is on foot, then I'd stick to those two places.
I guess she could take a bus to 23rd st which would be the next best choice. In another direction is Rumrill, but it is more about markets on that street than restaurants.
On 23rd, starting at MacDonald
La Estrella is a nice little taqueria.
Portumex is one of the longest running sit down restaurants. The seafood cocktails which can be ordered cold or warm are popular there.
El Tapatio is a good restaurant and has a 24/7 'taco truck' attached ... It's just a small takeout section that they added to look like a taco truck. If you want oysters on the half shell at 4am on Sunday, this is your place. The restaurant has good mocajetes.
There's a new place I keep meaning to write up called Los Mexicanos Deli which specializes in fruta picado, cut up fruit cups. They do a lot of fruit drinks and unusual combos such as the chamango ... need a major explanation of that but let's say its an aquired taste. Their tosadas are good and while they are nothing special, for some reason I like their tortas, though the pastrami torta turned out not to be a good combo as intriguing as it sounded ... don't mix queso fresca with pastrami.
I love ... love ... the al pastor tacos al vapor that La Selva makes on Friday and Saturday nights. IMO, there's none better in the Bay Area. They have a nice salsa bar as well.
Pepitos is known for their chile verde and has a lovely outdoor garden. Watch the board for seasonal specials.
Further up is San Pablo and Los Picados has some of the best tortas in the area.
In another direction but not too far from the hospital (though a car would be needed) ther is the Torta Azteca truck which has had positive reports
I haven't tried that one yet, but there are a number of taco trucks in Richmond, especially on 23rd. IMO, the restaurant food is better. However, here's my report on what I've tried and what I liked at each
After 5, the churro carts appear on 23rd. The one across from Portumex is the best
There's also a nice Guatemalan bakery on 23rd which is worth stopping by just for the smell of fresh baked bread. On Saturday mornings they make some snacks such as Guatemalan tamales and such.
Here's a list of the Richmond Mexican restaurants with addresses and reports. There are some in other areas but I didn't mention them because they are further out than where I assume your daughter works. If I'm wrong let me know and I'll give other recs
El Campesino does a really nice rotisserie chicken. They have added some tacos etc, but I haven't tried them. My guess is a chicken taco, burrito or taco would be tasty.
Next door at Plaza Ghirabaldi ... I'm not sure what is going on there. They went through a number of ownership changes in the past year. The problem is that it is way too big for a Mexican restaurant. For a while it turned into a weekend party venue which suits it ... if only they had checked the ages of customers. So it went through two more owners. I think it is Salvedoran now.
Not Mexican, but Mr. Pizza Man has Brazilian food. There is a daily lunch special that is better on some days than others. They deliver.
Sazon is another of those places that does owner roulette. I think it is closed again currently, but not sure.
Anyway Estrella is probably the best nearest choice. Hacienda Grill is still worth the trip
On the subject of Rotisserie chickens from Mexican places, Las Montanas supermarket in Concord makes a fine one too, and they include some lovely grilled green onions. The chicken itself is about $8, but as a combo meal with rice, beans, salsa and tortillas, it's around $10... enough to feed 3-4 people.
Concord has a lot of Mexican places along Monument Blvd. Richmond has a big Mexican population, too.
Living in Concord, she's probably not far from a good Mexican place. Seriously, there are some really great taquerias in Concord. My favorite Mexican places are around Todos Santos Plaza (El Farolito) and the Park and Shop on Willow Pass Road (the taqueria inside Las Montanas Super Market). I'm told that the Las Montanas Restaurant is good as well, but I've never actually been there.
Really good Mexican food in Walnut Creek is very hard to find, unless your idea of good Mexican food is along the lines of Baja Fresh and Chevys.