To clarify the use of the term "system wide upgrade"....the OP is a United guy/gal and therefore would like to fly somewhere United flies.

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You might want to start a thread on the United forum regarding flights on UA metal from SFO that are best likely to clear upgrades for 1ks. With the new equipment, upgrades don't come as frequently as they used to (fewer biz & first seats) and there is a chance you could get separated from your family depending on how many seats you are looking for. After you hear from the United forum with the best upgradeable routes, you could report back here and we could help you find a hotel.

Of course, maybe using the upgrades isn't that important to you in which case we'll just keep throwing out great hotels!