I see you are in PA. There are not a whole lot of true boondocking spots here in the East, especially if you have a 27' trailer. To me, boondocking is a dispersed camping spot in national forest, state forest, recreation area or BLM land that is not in a designated campground - at most there might be a fire ring. To others boondocking is staying for the night in a Walmart, Cabela's, a casino or Cracker Barrel parking lot, which I have done many times. To some it might be a campground that is considered "dry camping", a campsite with maybe a picnic table or fire ring and a vault toilet somewhere nearby.
The further West you go, the more true boondocking options there are. I spend many hours each winter researching Google Maps, recreation atlases, Google & Youtube searching for those ideal boondocking locations in wherever I am heading to the next year. I am fortunate to spend an entire month traveling out West every summer - this year I am focusing on Montana, last year was Utah and South Dakota. I try to alternate between boondocking sites and campgrounds, so that I can fill up on water and dump my tanks.
For example, here is one spot I stayed last summer on the shores of Flaming Gorge reservoir - 41°04'18.0"N 109°33'08.6"W
Here is a potential backup spot for this summer - 48°37'12.1"N 109°58'54.6"W
Back in the days when I was camping out of the back or my truck or Jeep, I wouldn't plan at all, but now that I am lugging around a 30 footer, I want a pretty darn good idea of where I am staying. I usually have most of my sites planned in advance, especially if near national parks or other destination places or around a holiday, like Independence Day or Labor Day. Today I just booked 4 nights in a campground just outside of Glacier NP. My first choice of campground was already booked in August, but I was able to get my 2nd choice. When I fully retire, I will most likely do less planning this far ahead and just go!