Never get under your bus just jacked up, always get something solid in there even if it’s a spare wheel and a block of wood. But carrying a trolley ain’t a good use of space. Whatever jack you are carrying and whatever spare you are carrying, have a practice at home, can you get the jack in there when the tyre is flat ? Can the jack get past the point needed to change the wheel from flat and both of these on all four corners too. I don’t like getting under with out decent axle stands minimum. If it ain’t solid, I don’t get under,,,,ever. When you service your bus and change stuff, if it was just servicing, keep the change out parts and bag and tag them, date, mileage changed, working order and why changed. These spares will be great because you know they work. Fan belt especially , bag it and tag it, sealable freezer bags are great, triple loop it and bag and tag it. it’ll get you home and you know it fits as replacements aren’t always available in ten minutes. Oil, at least a litre usually two in ready to dispense containers.I use one litre ex 80:90 gearbox oil containers complete with extension pipe and screw caps. Two of these in an Asda bag in the corner under the bed or behind the battery. Some electrical connectors with the screws, great for joining cables too. Electrical tape, wires fuses. Dissy cap, condenser, points, rotor arm, One long HT lead. 12V tester, spanners ,mole grips, pliers, sockets especially for the plugs and for the wheel lugs. Battery jump leads and a big old hammer just about does it, oha fuel pump and a matched rod..
Ozziedog,,,,,,,,,,,I bet there’s more too.