Originally Posted by
goodtasting
I could get 1 award ticket with SIN->Japan (start of trip, as part of item 1), and then Japan->SIN (item 14), and then choose anywhere between to add a free 1-way flight. For this option, though, I would end up having to spend about 27.5k United miles to get from Japan->HNL as part of my item 1 which might just end up canceling out the cost of whatever 1-way ticket I can get for free (or even negatively outweighing it considering there won't be as many 27.5k 1-way trip tickets I can get?)
There's no need to do this. You can combine SIN-HNL with Japan-SIN and still get an Excursionist Perk in between.
All that matters is that take one flight that begins in a given region, then take an intra-regional flight in a different region, and then the last flight of your itinerary finishes in the region where you started. So, SIN-HNL / ARN-BCN (e.g.) / NRT-SIN is perfectly valid, and ARN-BCN would be free.
Any region that you will visit twice is a candidate for an Ex Perk. Of course, I don't see many of those...
I wouldn't spend a minute trying to get SFO-SAN for free, though. I'd use it for intra-Europe or intra-South America. You can fly SFO-SAN cheaply on several carriers -- and I'm guessing you're not going to have enough miles to get the whole trip for free, so you may as well focus on using your miles for the most expensive flights.
Have fun! And... good luck with seat availability.