My wife has an adult trike and it is heavy. I put a front receiver on the truck with a regular bike rack. I had to purchase a removable crossbar for the bike. This goes from the seat post to the handlebar stem. They only cost about $20. I was then able to hang the bike from the rack.
I do use a lot of bungy cords keep the bike from moving around, but once it’s on, it is quite stable. It rides below eye level and all truck lights are visible. That’s the only method I could come up with, and it works for us. Good luck.
2017 Sunseeker MBS 2400R