Road side tool kit should contain at lease.
13mm spanner (adjusting tappets and other things)
3 screw drivers, stubby flat blade, and longer flat blade (carb adjustment screw etc), and a mid size Philips head.
A set of feeler gauges with 0.15mm, and 0.4mm (valve clearances and points gap)
10mm socket for distributor clamp.
17mm socket for wheel bolts
Socket for fan belt pully 20mm i think?
Adjustable spanner
Strobe
Pulse tachometer.
Pliers
Manual.
As for spares that will depend on your van and its engine.
as a minimum:
Pair of rocker gaskets
spare fuel pump
Fuses
Spare spade connectors and length of wire
5l of good mineral oil 20w50 etc
Full set of bulds
Spare fan belt
Length of fuel pipe
Coil
One or two ht leads
4 spark plugs.
Condenser and points for the dissy, even if you have petronix fitted (you never know when it may go tits up).
If its any thing more serious than fuel, ignition problem its probably best to get recovered home.
Hope this help Im sure there are a few things Ive missed.
Best policy I found was to do preventative maintenance at home, work through the bentley manual service steps, and make sure you do the basic regularly, oil changes grease beam and ball joint (early type can be greased py pulling small plastic plug out of to and screwing in grease nipple, only a couple of squirts of grease required) etc.
If you keep on top of thing you should have a good reliable bus.