Best type of allotment paths?

On our site the main roads (wide enough to get a car or council leaf lorry up) are basically compacted soil, rock chips and wood chip. Get's pretty muddy and those poor dears who have to drive right to their plot churn things up.
Between the plots there are paving slab paths (some are crazy paving) and some are wood chip.
I like the wood chip paths because they rot down and you can rebuild them, putting the old path onto the plot  - it's all organic matter.
The only real problem is that soil gets onto the paving slab paths and thin mud becomes very slippy.
Rather like the posh carpet paths though - most impressive

See, we just have rampant couch grass paths between the plots, most plots keep grass paths in their plots (or woodchips and/or weed suppressing membrane) and the main pathway is also grass... never have a massive problem with it being muddy, nor getting torn up by cars driving on it. Score one for living materials