the front wheels are locked because the key is broke off inside the ignition switch tumbler. What to do? Can I remove the tumbler and somehow get the key out, have a new key cut from the broken piece?

I would find some small needle nose pliers and try using them or a pick to remove the piece of key. You might first use the pliers to turn the broken piece to release the lock.

You can also put a rolling jack under the car (with wood to protect the car) and jack it off the ground and then use the jack handle to move the front of the car around.

You can superglue a toothpick to the key and pull it out.

Apparently locksmiths have tools for it.
https://youtu.be/kEv92zwta3E

Skip toward the end of this video for hot glue stick hack.
https://youtu.be/uh1dJKf1QtI

Super glue trick.
https://youtu.be/n6bPq_gsGok

Lots of ways to try on YouTube, assuming the broken piece hasn't been super-glued into the cylinder, lol.