A Frame is a good idea, inexpensive, easily stored etc.
Grinnall Scorpion 3 do one for their reverse trike and it only costs about £150.
From memory they weigh about 450 kg. You need to leave key in ignition so the steering lock does not come on and the mile meter does not go up!
[img]http://i448.photobucket.com/albums/qq205/talkmorgan/IMG_7537_zps128e9e91.jpg?t=1376418627[/img]

http://i448.photobucket.com/albums/qq205/talkmorgan/IMAG3076_zpse6ddbc82.jpg?t=1376418603

Anyone who like me who wants a trailer I would not consider just two wheels. Double axle must be the safest way forward. In time I would prefer an enclosed one.

2022 Plus Four, 2023 Super Three, Range Rover Vogue SDV8 and Triking T3.