Small multi-tip screwdriver, pliers, side cutters, allen wrenchs, a few tie assorted wraps, some electrical tape, some stainless steel locking wire, and now here's the important bit, ..
... a tubeless tire repair kit including the hole reamer, rubber plug insertion tool, 4 rubber plugs, tire guage and 4 of those little (20 gram?) pressured Co2 bottles. This will pump up the tire to about 32 psi.
And all this fits into the tiny box under the seat of an S4Rs!