Dorm RA jobs can be competitive, so there is no assurance that she will get one.
I find the numbers at these helpful links provided by ucbalumnus somewhat surprising and somewhat puzzling.
In both cases they seem to estimate the “additional costs” for someone living at home without a car at roughly $10K. That seems high to me. If your kid is occupying the same bedroom they always have it isn’t magically going to cost you hundreds more per month in additional costs. They seem to be assuming that the kid will start paying their parents a substantial rent. Unless the family was planning to rent the room out if the kid went away to college, this really isn’t a cost to the family. Food, maybe.
I’d be intrigued by Purple Titan’s suggestion in #15: 2 yrs at CC living at home followed by 2 yrs living at a UC?
They are probably assuming some of those costs as continuation of costs that parents spend to support the student while in high school (food, utilities, transportation including use of car / car insurance, clothing and similar items, spending for sports and social/extracurricular activities, etc.). These costs are non-zero, although since they are scattered around various categories of household budget, it is not necessarily obvious what their total is. Of course, they can also vary greatly from one family to another.
But also, some of these additional costs include books for college, which SDSU assumes will be $1,854. SDSU lists “room and board” at $4,316 for commuter students living with parents; presumably, this means food and utilities. Transportation and misc are listed at $1,542 and $1,450 respectively.
@Consolation Food is definitely part of the $10K. I’d guess that our D’s share of our grocery and dining spend comes to over $400/month, which lines up with the SDSU estimate for food/housing.
I think SDSU grossly underestimates transportation costs, which CSULB maybe addresses better in their generic “Additional Costs” number. Unless you happen to live in a location where access to public transportation between home and school is a viable option, or you can carpool with other students, I think a car will be a must.
When D got her driver’s license, our insurance went up $175 a month (and we did not change or add any vehicles). If she goes to school more than 50 miles from us and doesn’t bring her car, our insurance will drop $150/month. If she were to commute, she would need her own car. Add in additional insurance for the car and the cost of fuel, parking and maintenance and you’re easily looking at spending $500 or more each month that you wouldn’t be spending if she lived on campus (with no car).
I saw that. I still think it’s high. ( IME cost of books is often overstated, possibly depending on the major.) I think there is a possibility that parents can be unrealistically frightened by those figures if they don’t closely examine the assumptions. BTW, it doesn’t help that the CSULB table includes a double asterisk without a corresponding item below. One is left to wonder whether the single asterisk explanation is intended to apply. 
ETA: cross posted with shortnuke