Penn Park is pretty good. I think you would be fine there. I've lived there and felt safe enough. Kids ride their bikes around. Neighbors are friendly and respectable. Home prices are reasonable. There are plenty of older people there. I like Camelot and SilverTree neighborhoods.
It is a bit older of a neighborhood now, but still a fairly decent good family area. Not yuppy or wealthy-- middle to lower middle class working types mostly. It's not a luxury area. Plenty of older cars, not pricey cars. Same with houses. They're not luxury mansions of course-- they're mostly 1960s-1970ish slightly older homes, but most I've seen are kept up fairly well on the outside. Some dated inside, but that's to be expected with older comes.
Some crime, though not nearly as much as other areas:
It's a decent middle class neighborhood. Camelot and SilverTree don't have very much crime from what I can see. Usually it's out on Penn or highways that crimes occur-- such as at gas stations. It's not luxury, but it's definitely not bad. I lived there and liked it-- and there's a lot of places in OKC that I wouldn't live in. I would live in Camelot or SilverTree again any day, and would recommend it to my relatives who want more affordable but fine family neighborhoods. I wouldn't suggest granny go out to gas stations on Pennsylvania Ave at midnight. But, living in Camelot and SilverTree? Yes.
If you're looking at apartments in that area, I'm not sure about those. My recommendation is just for the Camelet and SilverTree homes in that area. If you stay out all night and come home at 3 a.m. or something, I might suggest Edmond instead-- just because Edmond tends to be very safe and parts of Pennsylvania Ave (gas stations, fast food places, highways, etc.) aren't the safest place at 3 a.m.. But, Camelot and SilverTree themselves are good enough for me. Most of my neighbors in Penn Park were pleasant working middle class neighbors who took decent to good care of the outside of their homes (for that price range... we're not talking mansion). They were fairly diverse in age and culture/race. Some young with kids, some retired. From what I remember about my neighbors, the cultural mix was half white or more, with some diversity in there too. I'm not sure how much that has changed. Might be even more diverse now. My neighbors were pretty friendly-- not nosy friendly, but pleasant if you passed them walking on the sidewalk. Most young families I knew were usually in their 30s, but I knew a lot of retired neighbors. Some had lived there for decades.I would live in those homes again any day. Apartments anywhere tend to draw a different class of people.