You're right that we could beat them, but I'm not sure we'd get the chance. I think they'd fall before we could even get help there. We'd have to get troops on the ground BEFORE they attacked. If they were 'conquered' I don't think we'd have the political will to invade. It would have to be either amphibious or invade KSA itself. I'm not sure we'd do either.
From this link "The US constructed its largest pre-positioning base outside the US in Qatar. Facilities were constructed in Qatar to support CENTCOM's prepositioning of military assets in the Central Region, in accordance with government-to-government agreements. The work is for both the Army and Air Force...< snip>The Army's newest and largest pre-positioned stock (prepo) facility opened in Qatar in August 2000."
In addition there are fully functioning Air Force bases in both Qatar and the UAE. Don't think that Pentagon planners haven't seen the possible eventuality of a Saudi uprising and taken steps to prepare.