Another aera of weakness for those ultra long range missions would have to be the first part of the inbound journey.
Massively overweight, the thing would have been barely able to sustain itself in the air during the first quarter, first third or perhaps first half of the incoming flight. Such an easy target. With only a remote tail barbette as a defense, that is, nothing. Unable to turn away efficiently, with very probable risks of structural failures if doing so. The sitting duck, golden lounge, VIP seat.
When encountering enemy fighters - even a Liberator ! - , an emergency abandon of the mission with the dropping of the bomb and some magical instantaneous dumping of the fuel, would not even have allowed it to out climb its adversaries, all the way up to very high altitude, where and only where it did have a niche.
To perform cross Atlantic plus some American 'trekking', distant outer Ural or cross Pacific missions the aeroplane would have to be, let's repeat awfully overweight at take off.
I remain convinced that it would require a solid tow behind a He-111Z if one wanted to avoid dedicated very long runways, not only of expensive constructions but noticeable and therefore bombed. All this, on top of the mendatory amount of rato rockets and jettisonnable landing gears (the standard He-177 undercarrige being itself well enough for the light landings.)
For missions departing
from South West France there would be a long ride across the Bay of Biscay (
https://maps.google.com/maps?oe=utf...cogne&ei=ZWoYUpS0HciIhQfynIGgCg&ved=0CJYBELYD ) where doubtlessly America and Britain could have deployed some curtain of radar carriyng ships, and a few carriers. Long range Mosquito and Liberator patrols as well. Especially when coupled with the 'killing' forewarning of Ultra intercepts and readings, eventually giving the time schedule as a bonus, we're bound for catastrophic losses for the Lufwaffe. Closing the show there probably.
Of course this part of the trip should have been carried out in nightime.
Let us grant the Germans for some display of them legendary procedural discipline and cool nerve in front of foreign adversity, and not try to depict too closely how they would achieve victory again in performing those acrobatic, take-off routines in the dark.
Hélas ! the US were about to provide radar 'pods' for their single seat Navy fighters (already?), and also we can easely forsee an emergency deployment of standard NF Mosquitos aboard carriers, for one shot missions taking off ('normally') from ships and landing home up there in England. A handful of such mossies aboard standing carriers would have brought down results.
There remains for the Super Adolfine to stick to low or very low flight to avoid detection, a one feat it was confidently able to perform at this stage of its mission.
But low level flight at night...
One could have witnessed however a good LW offensive against these shippings, using classical means at its disposal then. Quite spectacular and with open odds one should think. Short of a Marianna-class deployment in the Bay of Biscay of course... But what about if those damned Western Allies fancied some Overlording in mean time, with obvious goals at flashing through Northern France direct to Stuttgart ? Ach... un choix difficile.
Besides, some welcome vacationning trips for the Bomber Command and milkrun rides of the 8th Air Force upon the lovely dry pinhead flatlands and sunny drinkwater lakes hollidays paradises not-so-far-from-the-ocean such as these of Mont-de Marsan, Cazaux and Biscarosse, and a Bordeaux-Mérignac special, would have fast returned them to their original sand and dune nature of pre-Colbertian ages within, let's have a guess, less, or more than 2 weeks ?
For Norweagian departures to Artic routes bound to Northern America, the nasty low level dragging of hopeless Adolfine, above polar deserts should proove safer. That is again, short of any 'real angry' American settlement on and of the matter there too.
North Norway is not that large of country and possible aeras for major airfields perhaps not such a free choice. (
Google Image Result for http://www.gonorway.com/go/images/mapnorthnorway.gif )
There could be a good furtivity game to play for Germany there. Leaving no tell-tale traces of semi secret strips of random temporary pickings, yet requiring regular rolls back to German safety. Of the whole circus. It all becomes rather fuel expensive in the end.
Some combined Allied operations then, should become worthy given the relative smallness and remoteness of the whole suspect region. Not only throught air big stick usage, but with decent land complications as well. A look at the map will also show that this land is remarkably fitted for classic Royal Navy employ of the good old days, especially summer time, with an amazing portion of the territory under range of battleship canonade.
Besides in summer in northernmost latitudes there is no such place for a dark hide from destiny.
Perhaps some, well one, historical sortie of the Tirpitz in the finest bushido tradition.
So, appart from the usual rock crushing show of the 'big cars' and their British fellows, by day this time upon the few well known aviation fields dubbed suspicious, I would recommend for a flat-out general invasion of the land, or at least the settlement of permanent ground fighting there. That without much strategical disturbance of Allied main plans and means, yet very ennoying for the Germans if they wanted to put a fight, would sweep off the Northern Adolfine menace at the very minimum on practibility issues.
An ennemy tank across the runway being one of the two arch foes of the flying man.
The other being adverse weather. And talking about it Norway... as a place for rocambolesque departure, to be followed by lengthy polar experiments, to be followed by better documented North Atlantic general behaviour... for a plane designed and laden
not to withstand high g stresses... hm.
As for Soviet bound progressive morrows and the cruel first stages of every missions, above ennemy land all the way, the very careful detection of fast disappearing interstices in that 'solidifying' approaching soviet air phenomenom , would be mendatory devotion.
Night trips of course, for this beginning of the mission. Soviet weaknesses there. But easy Occidental help too : with such hopeless elephantesque targets dragging pain and sorrow throughtout East Baltic Sea, Poland Belarus Ukraine Western Russia Central Russia slowly evolving East, at low to moderate altitude, on their ways to still distant Ex-Katareninburg or Novosibirsk, I think that even third hand Douglas P-70s should do. (i.e. A-20 night fighter Havocs)
Again Norway departure bases for polar routes, eastern this time, should be required, which brings us back to preceeding paragraphs.
An interesting East Germany to Baltic Sea alternative could be devised, cautiously walking its way between Sweedish airspace and eastern red shores onwards to overfly Finland, then polar again before 'falling back' on Siberia either to strike mammoths specialities there, or more occidental tankograd conglomerates
from the back ending with a much, much safer straight-to-Germany return flight. A good possibillity while of course I haven't LAID ONE SINGLE WORD ON NAVIGATION prouesses along this thread.
Suffices to say that Finland, after some inner thinkings that belongs only to 'em finnies we have to guess, would sometime decide that well, after all... total forbiddence of any further German overflight with shoot on sight is more the order of the day.
In which case even a 1944 Mosköv Morane should suffice.