Re: What to pack??
Most important are hook up supplies for electrical, water and sewer. possibly cable TV and/or telephone, depending on your needs and the trailer.
You will want to be able to plug into any of 50 amp, 30 amp or 15/20 amp outlets, so need adapters from those to your trailer. An extention cord for your amperage is useful. I also carry 50 feet of true 15 amp extention cord for hooking up at non-standard locations. A voltage/frequency meter and wiring checker is a good idea to spot bad hookups before exposing your RV to them. If your RV is 50 amps, a 120/240 test light is a good idea to ensure the 2 phases are correct. And it is a good idea to have surge protection (SurgeGard is very good, and expensive) and/or under voltage protection (Autoformer, even more expensive).
At the minimum, you will need a (DRINKING WATER CERTIFIED, usually 'white') hose to hook to water. 25' is the best overall length, but you may also want to carry 10' for close hookups. 4' is handy in some cases, and I carry a 50' flat hose on a reel for those non-standard times. A pressure regulator is CRITICAL to avoid damage to your RV; get the best you can find. A 2 way Y with shutoffs is handy for when you have to share a tap; I would have a couple of the cheapest you can find, so you can leave it behind without qualms. I always put one in my water hookup, it allows me to depressurize the line before detaching it. A couple of brass 45 degree and 90 degree angles is helpful with some strange hookups, and a 5" flex hookup has saved me a time or two (there are some wierd setups out there). I like to run my water through a filter which handles down to bacteria size, to keep the worst of the crud out of my system. Before I drank the water, I would run just the drinking water through a purifier (too expensive and slow for other uses), or drink bottled water. Carry several spare hose washers. Also, to rinse out your tank, you will need a NON-DRINKING water hose (gray, or any color than white). Make sure you have an anti-siphon valve before hooking it to any drinking water faucet, the plastic ones break a lot, so get a good brass one.
Sewage is perhaps the most difficult to handle. First, start with a box of disposable gloves. The simplest hookup is a top quality hose and universal dump station angle. The best I've found is the flat hose from LevelUpp, but good luck finding that. The best corrogated hose I've found is the Rhino hose, but I have trouble with the fittings leaking (one of these days I'll silicon them). The 'blue' press fit system seals well, and the hose is not bad (and they have a new ultra heavy one which has promise). Their universal angle is the best I've found; their only drawback is their bayonet fitting is flimsy. The best fittings are the 'red' system, but they reverse thread things so you can't use them except with their hose. This will get you started. Next, you need a port into the system; the easiest way is a clear section between the hose and the dump fitting on your RV. They have straight, 45 degree and 90 degree, for any geometry. Next is tank cleaning, but we'll defer that till later, cause that is where the options really multiply.
For cable TV, at least 25' of cable, and a male to male adapter. I now have 50' and that still wasn't enough at one place (had to hook up to the site next door). If you don't have a cable hookup on your RV, they have a flat adapter you can run through your window.
A hitch, of course. Get one which you can lock, because truckers have been known to unlock RVers hitches and watch the fun as they drive off.
As for what you need in the RV, only you can tell. I like disposable plates, sturdy plastic cups, and real silverware, but your choices may vary. Whatever utensils/spices you will use for cooking. Cheap single ply toilet paper and holding tank chemicals. Towels and washcloths. A small wet/dry vacuum cleaner for corners and leaks. A small 'stick' vaccuum for the floors. A broom and dustpan. Dish soap, cloth and scrubbing sponges. A really good tire pressure guage. A spare tire pressure guage. Maps, a book of campgrounds, a 'Truckers Atlas' (to find low clearances), a book of truck stops. Road service subscription like Good Sam ERS. Passport America membership. Cell phone. Duct tape. Basic tool kit, including a 'RV screwdriver' (has those wierd clutch and square bits RV manufacturers like to use). An assortment of Bungee cords, plus some string and rope. Electrical tester (meter and/or test lights), spare wire, fuses, crimp connectors and bulbs. Some distilled water for the batteries. And so on.
Keep in mind the weight of whatever you load. Your best solution is to spend a few days in a park right next to sources of stuff, so you can run out and get the whatever, when you find you need it.
For storing the hook up supplies, I use the zipper bags from Camping World. One for extention cords, One for water hoses, One for sewer accessories (ok, 2, cause I carry multiple setups), and one for adapters (electrical/water). For other storage throughout the RV, I use various sizes of clear boxes/tubs with lids.
Sources, Camping World/RV parts stores for the RV specific stuff, Lowes/Home Depot/Ace/Target/Wal Mart for the general stuff.
We just bought a camper this year. To get it ready I used a premade list and deleated what we didn't need (like and ax). Each trip I add and deleat from the list based on new things I have though of and deleating things I don't need or are now already reside in my camper. Here is the list I used