All it takes is motivation, determination, perseverance - then time, and not least some money.
Lots of money reduces the amount needed of the other factors.
Limited funds? then need lots of the rest.
If I were serious, and wanted something sound to last decades, I'd first play with modeling foam and wood, then go shopping for engineering and fabrication help.
If it's just an experimental 'art project' then just do it, maybe get a local vo-tech teacher to make it a school project.
The underlying trailer could get registered, treat what's carried on top as a "temporary load".
To get specific help / answers you need to ask specific questions.
Lots of money reduces the amount needed of the other factors.
Limited funds? then need lots of the rest.
If I were serious, and wanted something sound to last decades, I'd first play with modeling foam and wood, then go shopping for engineering and fabrication help.
If it's just an experimental 'art project' then just do it, maybe get a local vo-tech teacher to make it a school project.
The underlying trailer could get registered, treat what's carried on top as a "temporary load".
To get specific help / answers you need to ask specific questions.