Here's the final photo of all the devices/cables I took. They had a separate bag and everything, which was usually within arm's reach. (Except for the laptop - that took a backpack!) You should be able to click it to enlarge so you can refer to the letters.
1) We took two cars out, and one car back.
2) I rode in my sister's car, ahead of my parents.
3) Her car does not have a working speaker system or cigarette lighter.
4) Radio in the south was, Kathy noted, all country. We don't like country.
5) Kathy was semi-joking that she'd fall asleep without listening to something in the car.
6) Long travel days meant short amounts of time awake at a motel.
7) We needed to arrange last minute travel details with family and friends along the way, usually with Facebook
8) Mom and Dad's car has two cigarette lighters which both work. One usually went to the GPS, and I used the other.
(A) iPod-connected alarm clock. Used to wake up to music most mornings. Also charges the iPod, (Q), and is therefore tremendously useful!
(B) Two USB extension cables. (J) enabled USB charging in the car, but it's a pain to have your parents in the front seat constantly changing cables and holding devices in the front. Plug in extension cables instead and I can do all the work from the back seat!
(C) My GPS, with a microSD memory card large enough to hold maps for the entire country. Mostly unable to charge in the car, which was a bit of a problem being the lead car.
(D) Dad's GPS, without a microSD memory card, so this one only had the SE part of the country (which remarkably reaches as far west as Texas). We suffered a little in Missouri where my GPS was the only one working.
(E) Power/charging for Dad's GPS (or mine, but this is his) via the car's cigarette lighter. This meant I couldn't charge mine. (Which you may recall was the only one that had the maps that worked in Missouri.) Worked great in the other car though, so they never had problems.
(F) USB charging cable for the GPS. Allowed me to charge using either (B) and (J) in the good car, or (K) or (U) at a motel (which is usually what happened)... or briefly with (H) if I had to.
(G) A friction mount for the GPS, as the legality of mounting it directly on the windshield is questionable depending on the state. Only have one.
(H) A battery-powered (AAA) USB adapter. Mostly used for speakers (S) and occasionally short emergency charging of ipods (Q, Z) or phones (Y, AA)
(I) USB charging cable for my phone. Not sure if it's a micro USB or mini USB or what the conventions are, but it goes to my phone, (Y).
(J) Cigarette lighter USB adapters, for charging anything via USB in the car. Unless you're in Kathy's car with a broken cigarette lighter :(
(K) USB adapter for a real outlet. Used heavily in motels. In retrospect I should have brought another one or two (we have several) as USB is how most devices are charged. Ended up having to use outlets on my laptop (U) a couple nights since I didn't have enough. I also used (Z) and (BB) once each I think, but they had dedicated devices going to them most of the time and weren't really available.
(L) Earbuds, for listening to music by yourself. I didn't actually use them all that much, but I did have to drown out the audiobook my parents were listening to. (Audiobooks from Cracker Barrel are a
(M) Portable WiFi. It's called "Internet on the Go" and came from Walmart (.com?). I pay for GB refills every now and then and it's considerably cheaper than using data on the smartphone. Of course it goes into roaming sometimes too... I used it frequently in the car and otherwise to get to important (seriously, some were) Facebook messages or general web browsing, especially on the way home when I relaxed more not having to copilot/keep the driver awake.
(N) Charging cable for (M). It really should be able to charge via (I), but I haven't had consistent success with anything but this adapter that it came with. Probably something to do with the amount of power, current, or voltage not being right.
(O) An ethernet cord. I took it in case Kathy would need it at college. But we set her computer up with the wireless adapter she used at home and that seemed to be mostly good enough, so didn't use it. I could've at a motel for faster internet a couple times though.
(P) Another ethernet cord I found on a table as we were leaving home and threw in just in case. On second thought it might be a phone cord; they look so similar. In any event, I didn't use it for the same reason as (O).
(Q) My iPod touch. Best device ever, except maybe for the phone. Supplied some of the music on the way out and most of it on the way home. (Kathy thinks the music on her iPod (Z) on the way out was better, but she's gravely mistaken.) It also has an amazing app for keeping track of which license plate *varieties* you see on a trip. (Colorado has about 120 different styles. Maryland almost a thousand.) The final count was 145 distinct styles from 40 different states. And a few aren't in the program.
(R) Charging cable for the iPod (Q). Used mostly in the car on the way home a couple times. Overnight charging was usually enough using (A).
(S) The portable speakers we used to play iPod music ((Q) or (Z)) in the car. Both ways. Mom and Dad's car didn't have a way to play the iPod in the car's sound system either. Powered by USB - in Kathy's car using (H) and (X), and in Mom and Dad's using (B) and (J).
(T) A USB powered flashlight. I read with this a little at the end of the trip by plugging it in to (B).
(U) My laptop! I used it a fair amount on the way home, mostly web browsing using (M). I also ripped a few TV episodes to it before leaving and had a lovely time watching a few, mostly on the way home. Texas is boring. 'Nuff said.
(V) A mouse for the laptop, (U). I hate the touchpad.
(W) Charging cable for the laptop (U). Usually went to the wall, but went to (EE) a couple times when I'd watched TV too long in the car.
(X) AAA batteries for (H). We only had 4 at home, and (H) took three at a time. Had to buy a couple more at an overpriced rate along the way, although we ended up not needing them. So three left in the bag shown.
(Y) My smartphone - taking the picture. Also invaluable for Facebook access. It went through a heck of a lot of power and was the hardest thing to keep charged, especially in Kathy's car with no way to do it on my own. We had to stop and have the other car charge it (and probably an iPod) a couple times.
Also factoring in:
(Z) Kathy's iPod + cable + USB wall adapter
(AA) Kathy's phone + wall cable
(BB) Dad's phone + cable + USB wall adapter
(CC) Mom's phone + cable + non-USB wall adapter, useless to me
(DD) Mom's camera + a rechargeable battery that plugs into an adapter into the wall
(EE) Outlet adapter for car cigarette lighter - just like a wall outlet. It's a bit of a large monster and I could usually go without resorting to it (see (B) for charging most things), but I had to a couple times for my laptop. Mom used it to recharge her camera batteries.
And, yeah, I even chose not to take the Kindle this time. I took some physical books and did a little reading on the way home. But I must say I preferred the TV and internet time in some ways!