I've read the rules -- crossings and stopovers and whatnot -- and came up with this routing. It has two overland sections. Does this look valid?

CPT - FRA (stopover)
FRA - SFO (stopover)
SFO - HNL (stopover)
HNL - AKL (stopover)
AKL - SIN (transit)
SIN - SGN (stopover)
SGN - VTE (overland)
VTE - BKK (stopover)
BKK - SIN (overland)
SIN - CPT (stopover)

Also, the trips going to be spread out across 6 months. I'd like to purchase my tickets as early as possible, just to avoid prices going up. I can buy tickets originating in CPT from the States, right? Seems like it'd be cheaper, and I can burn FF miles to get to CPT. How far out in advance could I purchase these tickets, given that the whole trip will span 6 months?