Under construction, very messy, but location is perfect to get into the city. You could easily…read morewalk, it just depends how much walking is too much walking for you. Taxi's are available outside the station, though. Do not fear.
The station itself with the information booth and coffee shop is very small, but there are a few shops in the local area you could go purchase food and beverages from - or wait until you're on the train, most still have a cart selling overpriced food, especially on the fast trains.
It appears to be wheelchair accessible, although I'm not sure if the elevator from the main street down to the station was operating. Check before you go as it could be unsafe using the steep entrance that vehicles use on a rainy day. And it rains A LOT in Santiago.