Believe I saw this about 40 yrs ago - early 1980's. The rear wheel tread has always stuck in my mind. I was going to ask if you picked it up in Colorado - later noticed lisence plate on your pickup. If it's same running gear an older gentleman owned it ad had it in a shed in his back yard in Lakewood Colorado - south of Belmar Muesum on Wadsworth. A very good friend of mine (Roy) had told him it was International Highwheeler - the gentleman who owned claimed that was incorrect (which I agree it is not IHC Autowagon). At time it was first highwheeler I had ever seen. In 1991 Roy and I traded several pieces of old iron - I ended up with a early 2 cylinder air cooled motor - Roy encouraged me to make a highwheeler out of it with an old buggy. Well overtime I have researched highwheelers in depth - currently building one like Roy had suggested. Why - because it's a challenge! Also highwheelers value has increased at a crazy rate in last several years - so buying one to restore is out of budget. Do have a Model A Ford, Autocar truck, tractors and gas engines.
Ok - so really have no clue on who made your highwheeler. I can say it's not International, Sears, Holsman, Kiblinger/ McIntyre (Black), Anderson, Sucess ...
What I can say it's very odd configuration. Front kingpin axle looks to be a combination of production car and blacksmith forged (spindles). Steering is most likely home made (large sector gear portion cut from a large gear possibly a pump jack?). Wheels - production models of highwheel era 1906 to 1912 typically have front and rears same size - modified horse buggies have different size wheels (first clue on being home made - unless it 1900 era). Rear differential axle - believe this is automotive. Highwheelers typically have differential on jackshaft with two chains to rear wheels (few had one chain). Planetary transmission - well this is very interesting design - in general they are very hard to find so you are lucky to have this. The jackshaft configuration of the planetary transmission is very odd - mounting above frame also looks incorrect - needs dropped down under frame or with hangers (like a line shaft). I belive planetary transmission and rear chain drive differential came off of same early auto - not a highwheeler.
So - I call this a piece of Americana - example of man's desire to build and modify. Could it be made to look better - yes. What do you have when done? Call it a period correct blacksmith autobuggy.
If and when I saw it 40 years ago it was only a running gear ... seat and gas motor were added later ... do not recall details of steering or planetary transmission ... it was rolled into a shed. Remember the tread on rear wheels.
Good luck with identification. Hope you find a period correct motor. Hope to see it a show.