The trailer was just a standard tilt trailer.

You'd want one with the wide base. Remember the Exploradome is 8 feet in diameter, at the legal limit without a permit. Too narrow of a trailer would be a real thrill in a high wind or passing semi. My trailer wheel base was 6.5 feet and that worked out ok, but, the wider the better.

The second thing is to get a trailer the right length so it tilts properly. My trailer was 10 feet long. When I picked up the Exploradome in Litchfield They mounted it up, and all the weight was behind the axle. Like a negative 200 lb tongue weight, yikes! I loaded it with 250 lbs of rock salt but it was still a hairy ride out to Nebraska. I only had about a 20 lb tongue weight on the way down there. As I'g get up to speed the wind resistance on the dome on the back of the trailer would make the trailer wobble. While I was there I had about two feet of the trailer cut off the back. This moved the CG forward enough that it rode fine. When I got home I replaced the bags of rock salt with two 75 lb workout weights. I would move one to the back of the trailer and that was enough to put the trailer right at the tipping point so I could tilt the trailer bed. So basically the Exploradome was close to perfectly balanced on the trailer. the two 75 lb weights gave it about a 120 lb tongue weight and it trailered fine. I'd detatch and slide one weight down to the back of the trailer and it would cancel the weight forward and I could easily tip the trailer.

Another option I never explored that might be easier would be to have a wide trailer and just transport the Exploradome upright rather than tipping it.

On the original rig, if I was ambitious, what I would have done is have the saddle on "I" channels so that the observatory could have been slid forward or aft on the trailer then blocked for transport. This would have eliminated the counter weights as the means of changing the CG.

Just as an FYI, the Exploradome 8 foot round building weights somewhere around 450 lbs.