If you install a second bulb in the Amigo's tail light housings and run the wiring directly to the MH's plug, you don't need any diodes--you're not really using the Amigo's electrical system at all. Its a lot of wiring to run, but it's less complex. If you wanted to use the Amigo's existing tail lights (ie, no second bulb,) then you'd need diodes but wouldn't have to run all the extra wiring. Much more complex, can't really help you on that one. But the second bulb thing has been done succesfully--my buddy's dad did it with his Jeep Wrangler for flat towing it.
2015 XLR Hyperlite 30HFS5 (mods being performed regularly)
2009 Salem LA 292fkds (gone)
Nights- ('12)23 ('13)23 ('14)15 ('15)31 ('16)25
2014 Harley Davidson FLHX (XLR cargo)
2014 VW Jetta TDI (diesel sipper, camping support vehicle)
2011 Ram 2500 CC 4X4 CTD, B&W Companion (toy hauler hauler)