Dolan described an engine about "four feet in the air", supported by two parallel "beams" on a rocky outcropping, with nothing else to identify what the craft/equipment originally was, other than some bones he and his friend suspected to be either those of an animal, or a "very small man". He indicated the skull and feet were missing (macabre, but an interesting detail).
Given that at the time, the wreck would've been thirty years old; I would assume that if the debris was situated in such a fashion that the engine was above ground, and perched within remnants of the frame, it would be reasonable to assume other metal parts, such as the instrument panel, parts of the distinctive cowling, and other items would've been apparent. Dolan clearly stated that he didn't initially think of it as being an aircraft...and he professed some knowledge of aviation as a pilot.
I've not found a detailed framing schematic for the re-enforcement made to the hull of the PL.8.01, but what images I have seen would indicate cross members, rather than parallel beams supporting the engine mounts.
I too agree that the engine would've been "notable", particularly if relatively intact...as opposed to compacted in the soil.
In (cautious) support of Dolan's theory...the area around "Old Route 9" would've been in line with both the intended flight path, and the eye witness reports further east of that position. If Nungesser and Coli made it that far before engine trouble, and were looking for a nice, straight patch of water to make an emergency landing upon...there's a great finger lake within a few miles of Dolan's reported wreck site-So nice, there's a seaplane "base" there today. I "flew" this route on a simulator linked to topography, and discovered that if making an approach on this lake, one would have to clear some surprising features. On a bad night, after more than 30 hours of flying, making an approach with a failing, or failed engine...I can easily imagine coming up short in some of those valleys at low speed.
Ultimately, what gives me pause on Dolan's account is that it was a) so long before he pursued a formal investigation...and b) that whatever he did see was so non-distinct that he didn't give it much thought until later on. It is just as conceivable that he found the frame of an old logging truck or mill rig in that area.