Let me know how much you are selling for...am in the market for an NA at the moment but a reasonably priced turbo might turn my head!
In terms of selling, I have sold 4 cars privately in the last 7 years and thankfully the current tech and retail climate makes it very easy. In terms of your questions:
You do not have to let anyone test drive your car, even if they are insured for it, its your car, but obviously not letting them test drive it might put potential buyers off. If they want to test drive they need to have fully comp cover with plenty of evidence (look for homemade print outs and ask them to bring a bill with their home address on it), when I bought my last VX I got fully comp cover for a week from a provider - some people even ask for a sizeable deposit before any test drive - remember its your car, you can decide who drives it whilst you own it :-)
Two best solutions for money transfer is direct BACS transfer, can be done sat in your living room online with the person stood there it usually happens very quickly. If in doubt contact your bank and get their advice. I think the longest banks say it would take is up to 2 hours but I have bought two cars like this before and it was over in literally a minute.
You can take cash but pay it over the counter at a bank, the great thing in towns and cities now is that banks open on saturdays making it much easier to do this route also (I remember banks only opening 9-3 on weekdays!).
Do not accept paypal, its not as secure as BACS.
I can PM you over a good receipt template as well if you want one that I made up (mashed up a template provided by autotrader and the AA).
Also when I sold my Celica recently I photographed it and videoed it being driven away by the buyer, they have a time stamp on it, just in case I get any speed tickets and need supporting evidence!