Why do you wish to be able to dissassamble? There would be different optimal solutions depending on whether it's for long term storage or if it's for transport or shorter term storage where rapid reassembly is desirable.
Build a telescoping main beam/boom. Front slides into the portion just under the seat, and is secured with bolts or quick release pins.
Depending why you are wanting to separate the two, you may need to install quick release connectors for the cables, as well.