A few questions I need answered!

Greetings. I just stumbled onto this board, and already decided I needed to register so I could post a question or two. I am a reserve deputy, and am looking for a patrol rifle. Kicking around the idea of an AR-15, but the Mini 14 keeps jumping up at me. I know nothing about either one, so here are a couple of questions for those that are in the know:

1. What is the difference in a regular mini 14 and a ranch mini 14?
2. Given the big difference in price between the ar and mini, is the accuracy really that much better in an ar?
3. I found a 183 model(I think it is a 183) for $350, might take less. If the barrel is not rusted and pitted, is this a good price? Don't care about the condition of the stock as I can replace it with synthetic stock.

Thanks in advance for any info you can provide.