TL;DR - I have an old, cheap bike that I leave locked up outside; for convenience. It needs some work and I'm quite tall, so it doesn't really fit me. Do I try to fix it up and mod it to make it easier for me to ride, or get another cheap bike that is a bit bigger? Any suggestions for a used, cheap bike that I can hop on and ride while wearing street clothes, with a fairly upright riding position?

Long version:

Hi all, I'm having a tough time deciding what to do with one of my bikes. I have an old Raleigh 3 speed that I got last year at a thrift store for $100. The reason I bought it was because I was in the middle of a major renovation, and my regular ride had a flat. It has locking wheel skewers and the key was packed away in a box, in the attic somewhere. I needed something to ride around on, so I got my cheap-o Raleigh that I aptly named "Ugly Alice".

I have since finished my renos and got my regular ride back on the road; which is great, but...I still have Ugly Alice. And I've found it useful to have a cheap bike, that I can keep locked up outside and just grab and go when I'm running local errands. I don't have to worry about it getting stolen and have put a rack basket, new seat and seat post, and grabbed new tires for it. All in, I've put about another $180 into parts to make it more useful. Many of these parts can be transferred to another bike, so I'm not too concerned about that; but I'd like to keep it on the cheap.

Here's where my problem comes in: the steel rims are just about toast. It's a 35 year old ride, and looks every bit it's age. Also, even though it's the large size, it's still a bit too small for me. I'm 6' 3" and Raleigh just didn't make bikes sized for me. The new seat post helped a bit, but it's not a great fix.

So, what do I do? I can get cheap alloy rims and lace them to the old hubs, which will help a little. But then I still have a bike that is too small for me. Alternatively, I could buy another used bike, for cheap, and fix up the Raleigh for my daughter to ride. Does anyone have suggestions for a bike that has an upright seating position, that I can hop on wearing jeans or shorts? My preference is for something used, that is cheap enough that people won't go to much effort to steal it (I have an orange series Kryptonite lock on it, on my front porch, in Toronto). I'd also prefer something with an internal 3 or 5 speed hub, because I'd prefer it to be fairly maintenance free.