my add-ons so far for my 82 westy

power amp for tunes with speakers
second deep cycle battery
pulled stock fridge and added a portable dometic that works better
two small generator sets (one on board all the time where fridge used
to be)
small lp gas heater
refitted all lp gas lines to quick disconnect types
had adaptors made to fit just about anything lp
added a 5 lb lp gas tank (hate to run out of fuel for coffee)
pertronix
power  inverter
second fuse box with everything in the back on it from the aux battery
lots of guages
back cabinet has
spare alternator
spare fuel pump
belt
plugs
oil (two stroke  and four stroke)
syphon hose

pending mods

new rear bumper (still in design phase)
new external 12v connector for aux system to gen set
way to keep water in liquid state in winter.
jimt