Did you get a trike tandem yet? If not, you're missing a lot of fun. I thought I would show you how I carry my TerraTandem on top of my 1995 Ford Escort. I am including pictures so you can make your own rack for your trike tandem if you want to use this method. All you need is a roof rack rated for about 100 pounds. I inherited my rack from a friend who bought a Suburban Assault Vehicle that came with a roof rack so he no longer needed the roof rack. I attached four slats of wood that I took off a palette. The rack came with clamps, but if it didn't I would have bought a long piece of ¾ inch aluminum, 1/16 thick, at the hardware store. You can play Superman and bend it around steel tubing with your bare hands, and I would have made some clamps to attach the slats of wood to the rack by making some u-shaped clamps with the aluminum. Here is my roof rack with the slats of wood attached

I had to make a trip to the lumberyard to buy two 2 by 4's. I got them 10 feet long. So far, the total cost is up around 8 dollars. I trash-picked the palette so the four slats on the roof rack were free. I used scraps of wood I had in my garage as cross pieces. I attached small pieces of wood where the front wheels go to help hold the tandem in place while I am tying it down. I cut two slots in the cross piece in back for the rear wheel by drilling a bunch of holes next to each other and then forcing the drill sideways to make the slot. I broke one drill bit. Rats. There goes another dollar. I then inserted a hose clamp that I had in a pile of junk. I wrap a piece of old inner tube around the rear wheel to prevent scratching, and use the hose clamp to hold the rear wheel. I hold the front wheel in place with toe-straps. I attached a piece of steel angle iron at the back so I could drag the back end on the ground without splintering the wood. Here is the rack:

Here is the rack viewed from the other end so you can see the steel pieces attached at the bottom to avoid splintering:

Next, I attach the tandem to the rack with toe straps holding the front wheels in place and the hose clamp holding the rear wheel. I place the rack and tandem facing the car from the side, and lift the front of the rack and drag the assembly forward and rest the front end on the roof rack. The picture doesn't show this, but the back end is on the ground. I am Mr. Wimp with a bad right shoulder but I can do this easily all by myself:

Now I grab the rack and tandem at the back end and lift the back end and slide the assembly forward, so the rack and tandem are balanced on top of the roof rack but facing sideways:

Now I rotate the rack and tandem so it's facing the right way, and use bolts in two pre-drilled holes on each side. I use locknuts and carriage bolts. I didn't keep track, but I am guessing that I spent around 5 dollars for all the nuts and bolts I had to buy. Certainly the total cost was less than 20 dollars since I already had a roof rack:

If I were going a long distance, of course I would remove the seats and carry them inside, and use some straps wrapped around the frame and roof of the car for safety. If I had some pieces of steel channel I would have proceeded differently. I would have attached two or three pieces of steel channel to the roof rack and made a detachable ramp out of steel channel for the front wheels, so I could just roll the tandem up on top of the car from behind and then detach the ramp. Maybe that will be my next rack.