I plan on carrying an array of metric sockets, wrenches, screwdrivers, pliers, etc. As well as anything needed to change a tire. So include torque wrench, breaker bar, and cheater bar. On long trips I always carry my safety seal plug kit. It just works. I'm looking at getting a good set of trim piece tools.
Oh, 3/8" breaker bar and codder pin puller. Both are obscure tools, but let me tell you about some MVPs. WORTH IT GET IT. Never had a car that these weren't used on. Heck even use them on my 2014 Hyundai Elantra.
Beyond that, I'm currently working on getting a GAP tool and putting together a set for jumper cables and a simple recovery kit (a spare strap and two shackles). For longer trips I'll bring my jump pack, but cables are always handy. Also for real 4x4 trips I'll have my nice 30ft strap, kinetic rope, etc. But that simple kit would work just fine if I needed to move a short distance.
I'll carry spare brake light bulbs and a brake switch. Seems like these two things will lead to all kinds of issues.
Soon I'll be doing the coolant system (truck has 110k, I believe in coolant system work at 100k on any vehicle) and at that time I'll replace the serpentine belt and pulley. I'll throw the old ones in the back just in case. Of course at this time I would make sure the T-stat housing, the plastic T-thingie, water pump, and hoses were all taken care of.
If I was driving cross country (aka, couple thousand miles), I'd carry a spare set of quality filters (Mann+Hummel or Wix, both available very reasonably priced off rock auto) and two spare ignition coils. They seem to go out in pairs. The filters, if I got into some bad dust or something, they are easy to replace. And if I had to get the oil changed somewhere, oil is easy to come by but the oil filter might be difficult. Could end up waiting forever for a shop to find a filter...and then risk it being a crap filter when it gets there. On the other hand, carrying $30 of filters when you know they are more expensive for lesser quality on the road.
A cheap small air compressor. Now this wouldn't be used for airing up and airing down, but for flat repair. A small cheap air compressor can easily fit under the 2nd row seats, and be a life saver if a tire needed to be plugged or the spare only has 5psi in it (because that seems to magically happen, lol). Obviously this wouldn't be used when off roading as I'd carry my ARB suitcase compressor.
Some sort of simple electrical kit, just to take care if wires get ****************. Get a couple of pigtails for crucial components. Pigtails for height sensors are $16 off amazon. Those are pretty vulnerable. Having a spare one of those wouldn't hurt. Try to identify the plastic clips used to hold wires and other bits of the car on. Just carry those as spares. So make sure I'd have the proper crimping tools, connectors, etc. These don't take up hardly any space and would be a life saver.
Gorilla tape and electrical tape. Self explanatory.
Otherwise, I believe that taking care of these vehicles with good preventative maintenance would thwart most issues. This is my plan for my Colorado trip this year with my LR3. But I'll be working mostly on preparation so hopefully I don't need any of this stuff. I'm going to be getting ahead on things that need to be replaced since I don't want to be wrenching on my trips.
Then again, I come from driving a 109 were everything is breaking all the time. I haven't had the LR3 for long enough to get a feel on how it'll do quality wise. But I think it'll be better than the 109.
