I would not leave a dog outside unsupervised in a yard, especially in Southern CA (I'm not that familiar with Ventura County, but I grew up in Orange County, which is very urban and very highly populated).
My reasons:
1) Maintenance-type people - where I lived, there was one phone/cable box for every 4 houses. Which means if someone had a problem with the cable, the cable guy might come into your yard to fix it. And might get bitten by your dog, or might leave the gate open, or otherwise cause a problem. I know there are restrictions about when people can come into your yard, but it's still not a situation I'm comfortable with.
2) Noise - barking, as others had mentioned. Your dog is a beagle, right? Aren't they known for barking? I know if I left Rascal outside the neighbors would be on the phone to the police pretty darn quick, because Rascal loves barking at noises, smells, etc. He would bark like crazy if left alone.
3) Safety - all it takes is one unnoticed hole dug under the fence, and the dog could be out of the yard unsupervised, with you at work. Add the unavoidable traffic of urban/suburban areas, and it's just not a risk I'd take. At least if you were home and he escaped the yard you could get him back quickly.
4) Safety - what if he gets into something in the yard when you're not home? Chewing on a stick and choking, eating a poisonous animal, who knows what. All sorts of trouble he could get into unsupervised.
5) Safety - especially with a purebred dog, I've heard too many horror stories of stolen "puppies" to not be very, very wary of someone wanting to nab my dog to re-sell somewhere.
Personally, I am 99% sure that Rascal does the same thing when he's crated and I'm at work that he does when he's not crated and I'm working from home - lies comfortably in his bed and sleeps the whole time. Since he's just going to sleep anyway, I figure the risk of him getting into trouble/danger by being left to his own devices far outweighs the minor inconvenience of being confined during my work hours, when he's going to be sleeping anyway.
When I have to go into the office, Rascal is crated from about 7:30 to 5 or so, and takes his dear sweet time to pee when I take him outside (which to me means he's not bursting at the seams, so to speak).
Congratulations on the (potential) new place - hope you enjoy the yard :)