Matt:
I recommend that you give some thought to installing a ferry tank system - something that will give you perhaps 900 to 1,000 miles of range.
I do a lot of ferry flights (just finished one this week from Canada to Peru), and I can tell you "for sure" that what takes all the time, costs all the money, and creates all the stress on ferry flights is the landings - not the actual flight time.
You can probably plan on paying about $1,000+ plus for each landing you make. This will take the form of terminal charges, customs charges, ramp fees, handler fees, etc. On top of all that, it's rare to be able to get 'in and out' of a fuel stop in a lesser developed country in less than 3 hours.
If you toss in a simple ferry tank system that will extend your range, you will cut the number of landings down, and that will greatly reduce both your stress and your expenses.
One flight per day of (for example) 6 hours in duration will result in about 11 hours per day of work - 6 hours for the flight itself, and about 2.5 hours at each end for the administrative and prep duties. Two flights per day of 4 hours each does not result in a 2 hour work increase, instead, it results in an (unsustainable) total of 4 + 2.5 +2.5 for each flight.
Note also that you don't need visas for countries that you overfly. In theory, you should not need a visa for a country if you are operating crew and are just making a fuel stop, but in practice, customs staff in lesser developed countries are not always well educated about the finer points of ICAO treaties.
Bottom line: Try and get a tank system that will let you spend 6 hours per day in the air, in one continuous flight. You will not regret it. Also, if the performance of your aircraft is such that you can increase your range by bringing along an oxygen bottle and flying at high altitudes, by all means do that.
Michael