I have an upcoming AS flight SEA-SFO and I will end up with a couple of hours to kill in the SEA airport. I have access to the United Club, which is in concourse A according to UA.com. I have three questions:

Are all the gates at SEA connected airside (I believe the answer is yes, but I'd like to confirm that this is still the case)?

How much of a hassle will it be and how long will it take to walk from the United club (concourse A, gate 9) to the likely departure location of my AS flight to SFO (I guess this could be in N, S, C, or D, correct?)?

My other option will be to buy a Boardroom one-day pass, but I'd prefer to use the United club since I have free access. My final question is whether the Boardroom at SEA is so substantially nicer than the United club that I ought to just buy the one-day pass regardless?

Thanks and sorry if this has already been asked and answered a dozen times. I looked but didn't find my answers.