45 to 1500 TP is a long way to go, and the implication is that you won’t make up any (or much) more “organically” before your year collection end. You said you were not fussed about losing silver, which suggests your end of year is not that far off - I assume it’s after 28th April.

Would it be more sensible to let your current status expire, then go for the same TP run in the almost-2-month grace period you have between that date and the end of your Silver card validity? That would give you nearly 2 years’ worth of gold status rather than 1, for more or less the same outlay.

(I do realise that it may also be a factor of when you can get time off work, etc.)

In terms of routing, I can’t help much - plenty of others on here are far more experienced with US runs, and I’ll defer to their wisdom.