Here is my go to course of action for buying off Craigslist.
1.) The first I do is inspect the ad, take a more in depth look, read between the lines. You can usually tell if someone is a hobbyist or just some guy who has had the machine in his basement untouched for the last 10 years after inheriting it. The description of the game and pictures alone can tell a lot. A description such as, "doesn't turn on, don't know how to fix it" can tell you a lot already.
2.) After seeing the ad, I will contact the seller. Usually I will email them, or text if they leave their phone number. After a few texts or emails I will usually call them or FaceTime them (even better in my opinion.) Again, you can tell a lot just by a phone conversation. Read between the lines here again, by now you should have a really good idea of who you're dealing with.
3.) I find that asking someone to pack up their game and haul it to meet up in a parking lot somewhere doesn't really work. They want someone to come take it off their hands, they don't want to do all the extra work. So I agree to meet them at their house or wherever the game is located.
4.) After obtaining their address, I will look it up on google maps. Not just to get directions, but to check out the general area. I turn on the satellite function and take a look at what the general area looks like. I also go into street view to have a look around the neighborhood. Again, you can gain a lot by these simple map views to see what area you'll be driving into.
5.) By this point I am very confident in my ability to gauge what kind of situation I'll be going into. If everything looks good, I proceed with the purchase. If there is a red flag anywhere I can at least call the seller and try to get any uncertainties cleared up. If they are willing to work with you, they are usually a stand up guy. If they don't want to work with you, you can always walk away.