some good advice above - the carsales advice is very generic so not particularly suited to selling rare collector cars.
So - talk to the potential buyer, gauge their knowledge of the model you are selling. What is their experience with older cars, have they owned one before and do they know what they're looking for/at? Ask them, do they have the funds available and are they ready to buy?
Check that they don't have to get their wife's permission first - there are a bunch of people who are just tyre kickers - and if they are serious, meet somewhere neutral and take THEM for a drive.
When I sold my Cobra, I only had two people look at it - they both flew in so I was aware they were pretty serious and they both drove it with me in the passenger seat. Plan out a route that YOU want THEM to drive - a route that will show off the characteristics of your car - hills, twisty roads etc, not a freeway for instance.
As a buyer, I would want more than a drive around an industrial estate to convince me, but here are my thoughts on vetting your potential buyer/drivers for a high-dollar car:
1] meet somewhere neutral
2] take them for the first drive - show what the car is capable of within your normal boundaries - rev limits, braking, tire use, cornering etc.
3] Tell them your preferred process for selling it is for YOU to drive them, illustrate the car. They should get a good idea of what it's like from that and that you expect to negotiate a price subject to a test drive BEFORE they test drive. If their intent is to low-ball you then no-drive. You should get a feel for how serious they are about your car and about buying it. Talk about HOW payment would be made? Bank cheque, or transfer etc before the car leaves your possession, amount of deposit etc. Then if you are in the ballpark or have agreed a price, they get to drive the car and YOU go with them at all times. Make it clear and get their agreement that - if they crash the car - they have to buy it for the agreed price no matter what, no ifs buts or maybes.
4] If they find a legitimate issue with the car, then you can negotiate - then there's little subjective bullshit about "ah, it just feels rougher than I expected, you should knock $10K off".
If it feels that rough, they shouldn't buy it.
5] At a minimum view or get a copy of their license.
6] Agree the rev-limit, speed, risk etc beforehand. You sit in the passenger seat and hand them the keys, do not walk around the car with the keys in the ignition etc.
Be realistic about the above, and be prepared to modify it to suit your particular situation.
