On the cusp of A-body ownership: Help me with a 1969 Valiant!

Welcome to the site, that's a nice car that you've got there.
I have a couple of '69 Valiants myself.
DO NOT disconnect the power steering and drive it! Can you say ''totally unsafe'' or ''liable'' if you get into an accident?
Mopar power steering systems are known for their light feel and twitchiness.
You can shim the relief valve on the steering pump to decrease the over assisted feeling that you have, just google Mopar Action Magazine and then go to the tech archive section and do a search. It's very easy.
Same place for a comprehensive set of articles on how to do a bbp disc brake swap properly. The article is called ''Disco-Tech''.
I like your idea to convert it to bbp front disc brakes, the stock 9'' brakes are terrible.
It should be easy to find Mopar wheels for it, they made millions of them. (Literally).
Don't cut up the radio delete plate to install a stereo, they are hard to find in good shape, and oh, the passenger side mirror isn't factory, that might be why it's giving you trouble.
I hope this helps.

I figured the P/S modification was a kludge, but it's the least of my concerns right now. I'll keep the shim in mind.

Ironically, I found the steering much scarier on the (partial) drive home than the brake feel. The distance between the gas pedal and the brake also scared the crap out of me at first, when I realized how easy it was for my big foot to pop off the edge of the brake and fly onto the gas. My braking motions changed entirely after that - now I move my whole leg to brake.

Mopar steel 14x6" rims? What would they have come on? Unless a Chrysler 5th Avenue M-body has a set, I don't expect to have much luck. Most junkyards that have old cars in this town weld the steel wheels together to prop the cars up in the yard. I've even considered buying one of these things out from under a car - it was a 14x7" steel Mustang rim; bit hard to come by and it hadn't been bent - and grinding the other wheel off.

She's staying radioless. I yanked the radio out of my '71 Mustang and put a factory blank-out plate on that. Radios are for listening in your house, cars are for driving.

If the passenger mirror isn't factory, neither is the driver's. They don't sit right on the doors at all to begin with.

-Kurt