I buy/sell stuff on CL all the time. Sometimes the deal calls for you to go around the back. Sometimes it requires you to bring people around the back of your own home. Sometimes you may even have to go into the basement. Alone.
The bottom line is there's no deal worth your life. If your spidey senses start tingling, abort the deal. Plain and simple, just walk out. Other than that, just use common sense and you'll be fine. Do what you'd normall do when meeting strangers and everything will turn out alright.
If your dad is selling stuff out of his bedroom and they can walk around the back, do so. It's not impolite or anything. Simply meet them in the driveway and say, "The stuff is around this way. We'll go in through the back door." There's absolutely no reason they should need to walk through the house. You can even sugar coat it a little. "It's a lot easier to get in and out back here. Come on back." Remember, as the seller, they're there on your terms. They should do what you say or they shouldn't do at all. If you'd like them to jump through a hoop they should. If not, no sale. Sorry.
As far as being there with your father, you should be there with him from the start. Be there to "help out" and be physically present, not in the other room behind a closed door. Your father can introduce you to the buyers. "This is my big strong son. He's here to help move the stuff while I supervise." That'll put the buyer's mind at ease and it'll also give them twice as many men to deal with from the very start. It's a lot harder to overwhelm two men than one. There's always the off chance of someone being in the other room but seeing two men from the start instantly doubles the difficulty of a robbery. Simply having a witness around can stop a robbery in it's tracks.
It goes without saying that you should always carry your handgun and meet in public during daylight hours if possible. It's also a good idea to have someone with you and/or someone who knows where you're going and when. If you're heading ten minutes away to do a deal and you're not back within the hour, maybe your wife should call someone or come check on you?
Common sense.
With all CL deals you should -
1. Get a name and phone number of buyer/seller
2. Get an email address
3. Get a physical address
4. Make notes of physical description, (vehicles too) license plates, etc.
Having multiple contacts is crucial. One email and going to someone's basement is stupid. Emailing a few times, talking on the phone a few times, finding out their address, etc., is all part of establishing a paper trail. At worst, the police will catch the bad guys. At best, they'll know they're already had before they try anything fishy.
