I'd check SFO/PDX/SEA airfares and get a car for a Pacific Ocean location - inland (including Portland) can have intolerable summer heatwaves as of late - not frequent but these cities (including Seattle) are not prepared when they hit. Coastal days, from SF northward are rarely above the 70s (low 20s C), and the 70s are a heatwave. The coast is relatively rugged, lots of outdoor things, and a myriad of charming coastal towns. Caveat that 4th of July might be $$$$$ in these locations. You are also much less likely to deal with nasty inclement summer weather in the central and eastern USA by taking a nonstop to the West Coast. You might find availability not so bad to SFO - there are 7 daily summer flights between SFO and LHR. BAx2, VSx2, UAx3.