The premise of this thread begs a point of clarity. What are the longer distances between fuel availability for the typical circumnavigation. Assuming the outlier long legs could be accommodated by fuel jugs, what is a reasonably long leg. A couple thousand miles? Carrying fuel for 500-600nm doesn't strike me as either unusual, nor excessive.
The longest leg of the "normal" tropical downwind cruising circumnavigation is 3,200nms from Galapagos to Marquesas. Its pretty damn difficult to get becalmed on that passage and if you do its going to only be for a day. Mind you Fatty Goodlander just finished that passage and must have been angry at the weather gods... and had a slow passage.
Then theres a number of passages about 2,000 to 2,500 long. But they are all really in the Trade Winds areas.
The Doldrums are only 120 nm to 200nms wide so its not really going to be a difficulty anyway.
As Jeff_H shows in his post, the Atlantic isnt too bad at all if you know where you are going. The Doldrums not very wide. The Azores High is large but you go around that, dial up whatever wind you want, really.
As aeventyr60 said, theres a huge chunk of Asia thats in the Land Above the Wind and you do need to motor a fair bit... but the ranges are short and the fuel is cheap.
A tropical circumnavigation just isn't that difficult. Most people over-stress about the irrelevancies (taking a wood router) instead of the important stuff (good satellite coms to download weather). I think the reason why many over-stress the irrelevancieis is that the planning phase takes years.. Job, boat buying etc, so to keep the dream alive they invent problems so they can solve them at the desk at work... and then scare the crap outta themselves.
Then they go home and read Survive!, watch Perfect Storm! and Adrift! and finally roll over and die like the Titanic!
(Never watch a movie or read a book with a !
in the title!
Remember, what you think is important is not. What is important can be picked up along the way.
Its just not that difficult