Andre, most of the topics you mentioned went through my mind in the past month. And one of the decisions I still have to make is how much the Son28 + dynamo lights + Plug + Cinq5 are important to me, how much is it worth to me second hand.
You're overthinking this business. The key thing is that you want a sound frame and wheels and transmission. The rest are trimmings. You have to take the no lamps/battery lamps/gennie and lamps already fitted if you're lucky, on the best frame you find -- very probably on the first bike you visit -- because you don't have time to mess around travelling huge distances by train, and the expense of travel by public transport in the UK will soon make a big dent in your budget. Believe me, I know all about this because I had a friend who would come from overseas to stay with us in Cambridge for a week and hunt classic cars -- most days he would see one car (with me driving him, and I don't tarry on the roads), and it would be utterly unsuitable and the price intergalactic wishful thinking, and some years he bought nothing in six or seven days of looking.
The key words are "a specialist bike", as someone said above. That's why Hoot's offer is such a stunningly right fit for you if you can afford it: a bike used and fettled by a cyclist with experience of the brand and activity. It's a sort of guarantee that you can't get any other place except in Bridgwater from SJS themselves, which is why I suggested them to you.
The reason that I'm so keen to convey these realities to you is that three times in the last thirty years I've carefully investigated travelling to a foreign country to buy a rare bike or just a bike without any distribution where I live, which is in Ireland, and each time I've instead delayed making a decision until I found some reputable helpful party (it helps that I used to be a handy linguist who still remembers enough of most foreign languages to make a little polite smalltalk before switching to English) to ship a new bike to me instead, which in every case worked out much dcheaper and less hassle, even if the delays took considerable patience.
I don't see that you need a huge toolkit. A
pump and a
patch kit and a
multitool will probably be enough. It's not like you're travelling to some Barbaricstan on the edge of the known world. The 2mm Allen and T20 torque bits missing from most multitools (but not the one SJS once sold and may still sell for its Thorn owners) useful on Rohloff bikes will probably not be required on a short tour; I can't remember when I last used mine. A
pedal wrench and the multitool's standard Allen bits will again be useful to disassemble the bike for the plane. If it wasn't to you he said it, get George to tell you again how long before he has to check in at the airport he arrives in order to disassemble his bike and pack it away.
How are you going to get the box for the bike to the airport? In fact, where are you going to get the box? I imagine an LBS will give or sell you a box, but they might not have a box handy because they trash them as the bikes are put on the floor or sold to be ridden away. As soon as you know at which airport you will leave from, find a nearby LBS and arrange by email for him to hold a suitable box for you.
Forget worrying about a Rohloff in Israel. In the ten years plus that I was the only Rohloff owner in Ireland (there might be two now), the only service my Rohloff required was an oil change, and if you've read this forum for a few years you'll discover that the few problems we hear about a) happened to known very high-milers, and b) have been designed out. The rest of what sounds like problems are usually just nervous newbies, or stubborn old guys who don't listen, having a panic fit because they heard metal graunching. It's one tough gearbox; by the standards of the mud racers for whom it was designed, touring is kindgarten use. Service it only with Rolloff-branded oils once a year or every 3000m/5000km, use it regularly, and forget about the gearbox; the rest of us already have.
In theory you identify the quick change link in the chain, squeeze in the middle of the side plates, and slide the plates off the pins. Still in theory, fixing the link in the chain requires you to position the side plates, squeeze in the middle again, and slide the keyhole slots over the heads of the pins, and bingo, you're riding again. I have particularly strong hands and fingers (a writer is a manual labourer -- he operates a keyboard all day long) and have never managed to do it without a specialised tool, of course sold by the same people who oversold the quick change chain links. The latest wheeze is that you need one tool to take it off, and another to put it on. In your camping kit you probably have another multitool with a small pair of pliers as one of the tools -- that will save you carrying two hefty dedicated tools. Or the chain tool on a multitool can be used in the middle of the link's side plates rather than directly on the pins.
By the way, if your camping multitool has a blade over three inches on it, leave it at home, get another, because in the UK you can be jailed, and you will certainly spend at least a night locked up until you can explain yourself to the magistrate in the morning, if the police catch you with a blade over three inches long. I'm not kidding you. Another painter was locked up in England for the knife he used to sharpen his pencil, and told me he was expected to wash and brush his teeth in the toilet in the police cell for three days until the magistrate held court on Monday and apologised to him "for the inconvenience" after he gave a demonstration of how to sharpen a pencil... Bizarro! For that much unhygienic "inconvenience" I could turn into a revolutionary again.
For the oil service, buy two of the small kits that give you one service, to get two syringes and tubes with threaded ends, one for inserting clean oil, one to extract dirty oil, then buy both the cleaning and the all-seasons oil in bulk; it's much cheaper. But you don't need to worry about that now. Ask the guy whose bike you buy if he'll service the Rohloff for you and watch what he does, instruction for you and a check that he actually does the job. If you ride a Rohloff bike around the block and it makes no complaint, you're good to go for a week or a month's tour.
The airline might ask you to drain the oil before you put the bike on the plane. George (Mickeg on this forum) has described travelling by air with oil in the gearbox and losing some of it. Sounds safe enough to me to leave it in and to tell the airline people if they're bolshie, "Oh, I drained it outside because I didn't know where I could dispose of the oil in here."
For a future long tour, you need to ask the many long tour experts here. I'm anyway a credit card tourer because my painting gear requires all the load capacity of my bike, leaving no capacity for camping and cooking gear.