So my 92 has nothing after the cat. I want to install a muffler and pipe but want to know if driving it 10 miles a day without one is bad,

 

My muffler and everything behind it rusted off so I have new piping and a new muffler coming next week. I took off the muffler and it has been running perfectly fine since then. It's been off for about 2 weeks and I drive it about 10 minutes every other day. Just make sure that the hot exhaust gasses wont melt anything. Sometimes it could put lots of heat on the floor and melt the carpet (one of the cherokees I looked at buying had that issue) but I think that would only happen if you leave it idling for a long time and not moving.

 

It's loud, that's for sure.

I drove my 95 for 2 hours from the sellers location to my driveway without anything behind the cat. It drove fine, nothing melted and though I did get pulled over it was for a tail-light - the officer said nothing about the noise.
(If you're wondering why I had to go 2 hours away for an XJ in rough condition it's because I insisted on finding one with an AX15 (manual) transmission and I6 engine.)

You should be fine - just be aware that the local laws may put you at risk for a ticket for the decibel level or "equipment failure" until you get a muffler on it.

 

Or if the floors have rusted to the point that they need to be replaced.

I have melted trim in my trunk from where the blowtorch heat came through the rotten floor pans while replacing my leaf springs. The rotten floor sections are repaired now, but I doubt I'll do anything about the melted holes in the trim since it's not affecting anything and cosmetics are of zero concern to me.

 

I got mine a month or two ago and it had the muffler on it but I dont think it helped at all. On top of the engine sound, it just rattled the whole way home. It has no inspection and it had a cracked tail light, no fender flares (PA is really strict with them for some reason), pretty much no muffler, and rubbing tires. It took about 2 hours to get home because we avoided lots of main roads. We passed 2 cops but we didnt get pulled over. By next week I should have everything ready to be inspected