For my two pennorth, I would give the petrol 75 a whirl. As Chris says, petrol is likely to be cheaper virtually wherever you go.
I've just bought a 4.5 petrol 80 (the 1FZ-FE engine) for some summer fun while I rebuild my overland disel 80. Having driven them back to back, I reckon that the petrol is, in some respects a superior machine. It's sooo quiet, more torquey, more powerful, can actually overtake at motorway speeds. Okay, so it's thirsty (about 20mpg), but that really is the only downside I can find. Compared to the diesel, it's also got longer service intervals and possibly lower maintenance costs in some respects (no turbo or diesel injection pump to worry about).
For me, the problem seems really to come down to range. If you can carry enough cheap petrol to get you between fills for the planned trip, then you're laughing.
Just an opinion. Now, I'd better get back to working on my diesel..... :-)
(04 KTM 640 Adv 'Naartjie'/11 KTM 990 Adv 'Tsumeb')