[DonC]

I've got a Crescent set in a fold-over hard plastic case that I got from Costco for about $100.00 that stays in the trunk and takes up very little room. It's suitable for "most" roadside fixes. Have a separate home made "roll-up" soft carrier with special tools (flat nosed pliers, channel locks, safety wire pliers, large adjustable crescent, big honkin common screw drive that doubles as a pry bar, and a couple of other odds and ends that fits in the rear wheel well.
Have a bunch of special purpose/ seldom used and miscellaneous tools in the garage that have been picked up piecemeal over time along with a full set of heavy duty impact wrench sockets.
Over all I'd say you need a full set of sockets and box/open end wrenches that range from an inch down to 1/4 for all around maintenance.
DonC