Thanks for all the input, really appreciate it.
Kayak is the winner for now, was the only option that got close to what I was looking for that I could figure out and use. So far has provided the cheapest round trip prices.
I couldn't figure out the google flights page at all. There was no calendar icon or flexible date option...same with hipmunk. Again, appreciate the input.
Didn't get to try hopper, since I don't have a "smartphone".
Thought I needed one for skiplagged at first, but realized I could use it on a PC. No flexible date option and no option to check multiple airports. Since I couldn't get a good proper search I was only getting higher prices, about $200 more round trip.
I guess I want to put out a challenge, can anybody beat ~$375 round trip based on my criteria? Again I'm looking to travel to the north east coast, New York NY, Hartford CT, Boston MA, Portland ME, etc. sometime around the 27th June (+/- 3 days) and returning on July 11th (+/- 3 days). I'll be departing/returning to the SEA airport in Seattle WA.
The current cheapest ticket is non-stop, but I'd be willing to make a stop or two for significant savings. I may need up to 4 tickets. If there's a stupendous deal that falls outside these ranges I'll consider it (I missed a deal for $28 one way ticket to NY).