You may not find places with the land that you want in Santa Clarita or Newhall; and you probably don't have to go as far as Palmdale or Riverside. I would suggest that you check Acton and the surrounding areas. I am up there all the time so please let me know if I can help you in any way.
Dear Leah, that's an easy question and can be responded with an easy answer, Please visit this link: http://www.alvarolozanorealtor.com/1-2-3_California_Search/p
Look at different cities at this page impute your needs and call me to make the arrangements to see the interior. I think we may find homes for these characteristics you mentioned with a SFR Home built in year 2000 or newer.
You will either be heading North (Palmdale) or East (Riverside). I actually see a couple properties in Palmdale and one in Riverside that immediately caught my eye--each has 4 bedrooms, 1-2 acre lots, Palmdale under $300K, Riverside under $400K. Is this sounding too easy? Let's make it that way. Get in touch.