The kickback is great to have, and one from a girls bike probably hasn't been ridden hard. It's probably in great condition.
However, the frame has a bend in the down tubes. I saw one like it last week. This pic is from the 64 catalog, notice how the head tube and seat tube angles (slant) are the same? On many women's bikes, the frame bends in the middle, throwing off the geometry and may make the pedals come closer to the ground. You may be able to ride it with no problems or it may continue to bend.
"There is an app for that". Really, you can get an app that measures angles using your smart phone or tablet. Hold it up against the seat tube and again on the front of the head tube to see what the angles are.
Since you have a pretty good side shot, i can measure from here (using the bottom of my monitor as a level reference)
Head tube angle 66.3 degrees
Seat tube angle 72.6 degrees
in the catalog shot:
head tube 70 degrees
seat tube 70 degrees
Yeah, as the bike sinks in to the ground, the head tube lays back and the seat tube tilts forward.
Pretty good eye there Wildcat. I've seen plenty of girls frames and girl back tandems bend mid-seat-tube but never noticed any like this bike.
An easy test for a bent seat tube is to put a straight edge against the rear of the seat tube near where the upper down tube meets and look for a gap. After that is straightened out, a second seat post pushed all the way to the bottom of the seat tube will reinforce the frame.
We have a tandem with a bent ladies rear at the local coop. The other mechanic brought in a screw jack of his own making to straighten out the frame. I'll try to get a photo tomorrow.
Many girls bikes have an extra tube in the frame. A stubby bit between the down tubes. I suppose this is why. See this photo for an example. That probably added $0.50 to the manufacturing cost.
Here are a couple photos of the frame tool a friend made. Consists of a piece of heavy pipe, a heavy threaded rod, a large nut and two washers. The one end of the pipe is curved to grip better. The end of the rod could be curved but in this case it gets trapped by the seat post clamp. Total materials cost is under $10. Use a bfw to turn the nut. This allows slow and controlled pressure.
WOW. Thanks @Wildcat and @rickpaulos for catching that. I had a bad feeling when I first got the bike home and rode it up and down the block... my toes seemed REAL close to the ground as compared to my '68 Panther, which I thought should have been similar. So I measured it and this one does in fact have an inch less ground clearance at the pedals and at the BB than the Panther and my '64 Fleet. I figured it was bent, and talked about it a little on a Schwinn-specific forum... now you guys have confirmed.
That straightening jig seems really cool. I saw another forum where guys have made gizmos like that with a scissors or hydraulic jack, though they were using them against the BB to straighten forks. Same principle, I guess.
Not sure if I'm going to try to straighten this one or find a better frame, maybe even a boys' model. What I want to know is how did it get bent like that?