Which single pilot jet has the largest cabin and longest range? I'm looking to rent a jet for a trip round the world with my friends but also since I have my license and MEIR, I'll be able to fly myself and don't want to hire another pilot.

Which single pilot jet has the largest cabin and longest range?
According to Wikipedia's list of light jets, the longest ranges (for single pilot certified jets) are:


SyberJet SJ30: 2205 NM
Pilatus PC-24: 2035 NM
Embraer Phenom 300: 1936 NM
Cessna Citation CJ4: 1927 NM
Cessna Citation CJ3+: 1825 NM


Sorting by max. number of passengers, we get:


Pilatus PC-24: 8-11
Embraer Phenom 300: 7-10
Cessna Citation: 8-9
SyberJet SJ30: 5-6


Considering you are already rated for the Phenom 300, this is likely your best option. Anything larger will always require a minimum crew of 2.