The shows are hosted by the Tri-State Gas engine and Tractor Association, 22nd-26th August if I remember correctly:
www.tristategasengine-tractor.com/Motels in Portland and Decatur are usually booked years in advance, but there are other towns like Muncie with rooms available, we stay in Muncie ourselves but we do book early. Nearest airport is Fort Wayne (FWA) and you can get connecting flights from Chicago, detroit and other hubs.
It's not difficult to find accomodation if you don't mind a shortish drive, and Muncie has far better shopping and other facilities.
Our travel itinerary this year sees us fly into Detroit, stay locally for one night, visit the Henry Ford Museum and then work our way south, visiting our friends in Temperance, MI, then on to Bryan, OH to look at the big Nordberg generating plant there as guests of the admin people, then we go to Auburn to look at the Auburn-Cord car museum, then down to Muncie. Motels are all booked along the route.
After the engine show we go to Dayton, OH to renew our USAF Museum subscription and have a look at the latest exhibits, that's a couple of hours drive from Muncie, but very nice back road routes for most of it until we hit the outskirts of Dayton.
We drive about 1500 miles in the 8 or 9 days.
For us it is a relatively cheap holiday as the US$ is quite low against the UK£.
Pictures, we take up to 1500 in the week, and a show report comes onto our website a few weeks later. The motel has Wi-Fi internet connection for free so I take a small laptop (Toshiba Libretto) to collect email and to start picture editing. I usually spend a couple of hours on the flight back doing pictures as well, there's a lot of work involved!
We would be very pleased to meet up with other guys from this forum at the show.
Peter