Especially with the power crunch in California right now, there may be some nice incentives that will allow the solar roof to fit into your budget. Consider installing more insulation in your attic and possibly an attic fan. You could also look into adding insulation to your walls, and make your house ultra energy efficient. The peak time is during the day, when businesses use the power as well. The off peak times are usually around 7 p.m. to 7 am Monday through Friday, and all day Saturday and Sunday.
Tax rebates are available in certain states.
PV power cells can be very expensive but the return on investment may be worthwhile. I took out all of my Malibu lights, turned my decorative pond to circulate for an hour a day instead of 8 hours. I have changed every single lightbulb to fluorescent bulbs. Anything nonessential is turned off unless I need to use it. If her water heater is electric, turn it off.