I haven't fished my 4 pc Loomis IMX 9 ft 5 wgt for years but took it down to the stream yesterday to slap the water. I forgot what a pleasure it was to cast. That rod would get my vote as the "behind the truck seat" emergency rod. Throw on a CFO and your in bid'ness.

Flies? GRHE and Pheasant tail nymphs in assorted sizes. Followed up with kauffman simulators, griffths knats, adams in assorted sizes. Have an emergency streamer handy for the hogg sitting beneath the undercut bank.

I own a very durable pair of Lacross hippers in case you don't want to get your feet wet. I think all of this would fit behind the truck seat.

First off, I never go anywhere without the gear behind the seat of the truck. I always keep a complete 4 piece setup in it's case behind the seat and my main rod in the overhead shelf-it unit. And the fly boxes have been consolidated down to 3 small boxes which fit the side pockets in the doors of the truck, along with the necessary foreceps, pliers, and fish handling gloves.
And the waders are the NEOS Hippers, rolled up to the size of a pair of sneakers tied together, and stored behind the seat also.

Besides, if a person that much of a fly fisherman, how can a person not take some fly fishing gear with them when travelling like that?

I keep a 6 wt., and a fanny pack in the back of my truck almost all the time. In the fanny pack I'll usually have extra leaders, pliers, dry fly dressing, and as many fly boxes as will fit, usually 2-3. For flies, I stick mainly to small (#17-20) parachutes, caddis, and stimulators, but I also keep different colored wooly buggers and hoppers too. Might want to throw in some wading socks too.

just a box of your favorite flies, a 4-piece 5wt rod and a matching real loaded with line, waders, spools loaded with line, average tools. Nothing special, after all it is an EMERGENCY fishing kit. It is very small as it is so few items so it is easily stowed.

I don't fish for trout, but I do keep a two-piece rod, with ten pound test. I keep extra hooks,sinkers and have an assortment of tried and true lures that cover the deep to the surface.

When warmer water and temperatures finally arrive, I always keep my pond fishing necessites in the truck, which includes,at least two fishing poles, mostly three, so I don't have to keep changing lures and a fanny pack full of goodies!

I have my fishin' buddy on speed dial and I've gone fishin'!

In a small tote bag I always carry an inexpensive 3wt 7' set up. The size is manageable and long enough for any stream. I include one box of flies w/ Adams, PDM, BWO, Royal wulffs, Copper John, Prince, Squirrel Tail, Sparkle Pupa, Zebra midge, Red Midge, San j worm, very light streamers. There is always a bag of unsalted Almonds, nail clippers and hemostates, two bottles of water and my firestarter, light jacket and a cap. Since it is my emergency fly kit I've made a copy of my license on similar colored paper to the original. Now I'm set for any stream that comes along. (I also tuck in my small first aid kit.)