After 34 years....

[LunaSea]

11. Did it quit heating or quit spinning? Or both?

Lack of spin, but still heating may mean a broken or slipped belt, a very simple repair.
Lack of heat may mean the coil has died or melted the fuse.
Sometimes an object or material can get lodged between the drum and body and can jam the drum, which can lead to motor failure.

Just know that a newer replacement will not have as sturdy a constitution as your old one. It will be infested with IC chips which will likely fail before the mechanical parts do.
I've got a pair of 20 year old Kenmores myself and plan to keep them up and running as long as parts are available.
Plus I find a ton of change and guitar picks every time I open up the dryer housing!