So, thank you FT'ers all for the help. I ended up sticking with US flights, as I could not find anything with UA that fit my schedule while still keeping under 29,000 miles. According the GCM, I am now at 28990. Everything is confirmed, and for some reason, on my last leg, Thai has only let me assign rows 1 - 4 (i.e. first class), will be interesting to see how that turns out. Regardless, I am very happy today.

Here is my final routing;

1 SK 525 D ARN-LHR
2 AC 889 C LHR-YOW
3 AC 441 C YOW-YYZ
4 AC1256 C YYZ-CUN
5 US 316 Y CUN-PHX
6 US 045 F PHX-KOA
7 UA 879 D HNL-NRT
8 NH 909 D NRT-HKG
9 SQ 891 D HKG-SIN
10 SQ 225 D SIN-PER
11 SQ 216 D PER-SIN
12 SQ 970 D SIN-BKK
13 TG 960 D BKK-ARN