Odds are 50/50 that if you ask, you will get permission. They will either say YES or NO.
Really. Odds are 100% NO if you don't ask.
I have asked and received permission at HUNDREDS of private homes. I figure that I've had a YES at somewhere around 60-70% of them. These are people that I have NEVER met before they answered their door. Most folks are VERY curious about what might be hiding around their homes.
You can increase your odds of them saying YES by being friendly and polite and positive and interested in them and the history of their home. Older folks LOVE to talk about their homes. Do you like people? Yes? Then you can do this. If you are a grump and spend your hunting time grousing about your bad luck, this will be difficult to do on your own. You may need therapy by tagging along with somebody more positive for awhile.
The only qualifier I would suggest is that you have clean and neat recovery methods. You may only hunt the place that afternoon. The homeowner has to look at the results of your recovery methods for the next few weeks. When the weather is dry, I will make sure to water any plugs that I've cut in the lawn before I leave, just like I would at my own house. I take the time to make sure that everything has been replaced nice and neat, like at my own house.
And make sure that you say thank you before you leave. They will appreciate it and you owe it to them to say thank you for letting you look around. Most will invite you to come back ANYTIME. I am serious.
A number of years ago, I put together a club presentation complete with slide show on how to go about selecting an old home to hunt, how to go about getting permission to hunt and then where to hunt once you've gained permission.
For many of our club members, this was all great information, but it really boiled down to most not having the confidence to go up and knock on a door and meet a total stranger. That is a bit of a scary big step for most.
While I live out West, I know that people back East are nice as well. I've hunted back in Pennsylvania and met lots of nice folks there. Wow, you guys have so much old territory to hunt!
So, put on a smile, ring the doorbell and away you go.
Rich (Utah)