I have a few stories for you on this one:
When I bought my 172, which was my first plane, I was lucky. The plane was a 1 1/2 hour drive away. I called the guy up, got a few details to make sure it was worth seeing, but didn't ask a whole lot of questions. I hopped in the car, drove out to see it and offered him on the spot. Came down a few days later w/ my mechanic and we did a pre-purchase. That was easy because it was close.
When I bought the 152, I called the guy and he sent me some old pictures. I was in So. California and he in eastern Wyoming. I had to call him quite a bit and it was tough to get good answers out of him. I felt it was a good bet anyways and found a mechanic out there locally that would be able to do the pre-purchase. Flew out there and the plane was ok, but some things were not mentioned or as described. Still I had spent all that money, plus the excitement factor, so I had the mechanic go ahead. He found some things, but I later found out there was a lot that he did not find. In reading the logs in detail, I also found that he and the owner had done business on the plane frequently in the past and that they must have known each other although they did not act like it. It has cost me close to $6K to get N714VG to what I consider to be impeccable mechanical condition. I could have avoided that by being a more savvy buyer.
The third plane I bought was a Grumman Tiger. I was in in Southern California and the plane was in Nebraska. It was February. I called the owner and spent a good deal of time talking and emailing him. He sent me lots of hi resolution pictures that I could zoom in on and lots of detailed information. He had no problem in answering my questions no matter how many and how detailed. THAT helped immensely in helping me establish what this plane was about. I was fairly sure this was the right one for me so I booked a flight out there w/ my mechanic (yup, I took my own mechanic this time) and we shared a room etc. He quoted me a straight up fee for the trip and inspection and I paid his airfare and gave him an expense travel allowance. The plane was a cherry. Ended up we couldn't bring it back that trip, so I flew out on the airlines again on my own a few weeks later and picked it up.
When I sold the Tiger, the guy that bought it from me was from Oregon. We talked a bit on the phone. I set up a very detailed website on it (yes, information does sell as long as its a good story you have to tell) and he came down to see and fly it. He screwed up by having some mechanic neither of us know do the pre-purchase. This guy took him to the cleaners (while I held onto a $3,000 cash deposit for security) with a bill that was close to $1,000 to replace stuff that did not need replacing. What is more, he did this replacement stuff without the buyer's or my permission which was against the terms of our pre=purchase agreement. He refused to release the plane and threatened to put a lien on it at which point the buyer coughed up the $1,000 and all was well. I did not have to pay for any of those "unairworthy" fixes because the prepurchase stipulated that I would fix any "Squawks" using my mechanic. Point, is, the buyer would have been better off, in my book, to have his mechanic come down and do the pre-purchase.
I have lately been looking for both another Grumman Tiger and another 172M model and have done a fair bit of calling around and in one case traveled to see a plane.
Here are some tips I can offer from all of these collective experiences:
1. Talk to the seller, his wife, his mechanic, and anyone else you can dig up that is associated w/ the plane and ask a lot of questions on condition, history, etc. Don't be afraid to get really aggressive with the questions and to be too detailed and to press them for answers. Be respectful, but go for the information. The more info you have, the better position you are in to make a decision to go see it.
2. Get as many high resolution pictures of the plane that you can. Use them - zoom in on them to see the things you want to see.
3. If possible, get a person that has absolutely no interest in the plane or transaction to lay eyes on it. Give them some questions to go find out for you (does it have shiny aluminium in the wings and tailcone, any exterior corrission, glass condition . . .foggy, scratched, crazed or crystal clear, like new ?, describe all dings, dents, damage to exterior, paint condition,, firewall condition, etc. . . . a club member would be great. I don't recommend having a mechanic on the field look at it for you because they might have the mind that if they can steer you into coming out there then they will be the one that can do your pre-purchase.
4. It does pay to get copies of the logbooks. Look back at least 5 years worth. Beware of planes with "rubber stamped" annuals. Look for planes that have had a consistent maintenance and upkeep record. A plane that has had a lot of things fixed on it within the last five years is a usually a good thing, not a bad, because it means a lot of the broken stuff has been searched out and taken care of. For example, that Tiger I bought had a TON of money invested in fixing up everyday things on it within the last few years of ownership. When I got, it there was nothing left to fix. Same thing w/ my 152 now. Paint and interior are not 10's (I'd say they are a solid 7) but baby the plane has nothing left to fix 'cause I fixed it all in the past two years I've had it.
5. Go with your gut. If you feel like you simply are not getting the information you want or need or that the seller is not answering your questions properly or to your satisfaction and you can't get them to, then mark that one off your list. It ain't worth the time and money you will spend to go see it. You need to be able to discern what this plane is before you go see it and use the trip to see it just to confirm you are right. Don't travel to see if the plane might be what you are hoping it is - it gets too expensive that way.
I've also found that if you have time, sooner or later, that right plane will show up relatively close to where you live and when it does, be ready to jump and don't be afraid to offer what it is worth. Time and the money to travel back and forth can get mighty expensive.
Hope this all helps !