West coast to London flights in June

Trying to go to England (from Seattle) mid-late June. I know that summer isn't ideal for Europe travel, but I work in education and that happens to be when I have the time off. Flight prices are pretty high right now, around $1500 with a checked bag, and I'm trying to gather options for making it more doable. Family suggested using air miles to fly to NYC and then purchasing a JFK-LHR flight, or flying to a less popular European city (ie Brussels) and taking the train over to London, though I've been to Europe before and I know train tickets can also add up.

Thoughts on doing one of those things instead, or should I wait and see if prices go down closer to travel time? I don't want to wait too long and risk booking it last minute, I feel like I'm already almost cutting it too close, but I've read that prices do fluctuate a bit closer to date of travel. Any insight? Thank you!