Let's say you live in downtown San Francisco, spending 2500 for an old 1 bedroom apartment. You can't run out your front door...might get hit by an uber driver or dude on a fixie. Way too much traffic. Sure you could drive 30 min to Marin, but then again, you don't have a car because parking it at your residence would cost 300/month. So actually, you can't really drive anywhere. Ok fine, you can take Muni 30 min to GG Park. And run the same boring loop you run every day. And have to take Muni park to your apartment drenched in sweat. San Francisco is a terrible place to live for the runner unless you have tons and I mean tons of money. OP is from Ohio asked for affordable places. Be realistic.
Ok fine you say, live in the Easy Bay. Still way too expensive, but cheaper than SF proper. I used to live in Berkeley and the running there was actually not that great. Yes, some trails in the hills, but getting up there usually meant getting in the car. Running in Berkeley itself was terrible. No flats, too much vehicle traffic, too many cross streets, overgrown sidewalks, aggressive crackheads. There is a reason the Cal track team does a lot of there running on the grass field at Edwards Stadium! Not the best option.
South Bay...again, criminally expensive. And again, if you live in downtown San Jose or anywhere near it, terrible terrible terrible traffic getting anywhere.
I'm not saying the Bay Area doesn't have good trials. Just saying that to live near them, you need tons of money. Sacramento overall is way more affordable (even the best areas) and the trails are just as good if not better. And in Sac you can afford to have a car, and drive to other close by trials on the weekends (even Tahoe) if you want no sweat. Sac traffic can be bad, but it's nowhere near as bad as the Bay Area's.