Hi Dan,
I'm afraid that the buying process is a bit different for "land only/cabin" in our areas. We have an off grid cabin and land we purchased (upstate NY), but it was financed from my father in law (easy peasy). I have looked at several places closer to us that don't fit the standard house/yard/etc. and there very well might be different financing required if you need a mortgage. There are experienced land realtors/finance people out there though. If you need to purchase a mortgage to buy, with a traditional home loan, it will need certain basics, i.e. septic or city sewer, running water, etc. If you are able to pay cash however, your options really open up. I don't have anyone local to you to recommend, but this website allows you to search Bucks county GIS
http://www.buckscountyboa.org/pt/search/commonsearch.aspx?mode=address by address if you find an area you are interested in. If you find they are out-of-towners, you might want to contact them to see if they are interested in selling directly...