The guts of the room are brand new - I suspect that it is probably in the same location and size as the old Mission Inn - but I don't know. Two treadmills, one elliptical and one bike - all Precor machines. A full rack of dumb bells and a (curling?) bench. There's a number of weight exercise balls as well as an inflated exercise ball. Towels, water, a medical weight scale + a flat panel TV are all available.
The 4 machines look outward from the Fitness Room toward the second floor central entrance - which looks out toward the garden and pool. One way to think of it is that this property is shaped like a wide V - sort of like the angled parts of the letter "K" - with the mid point of the V as where the slope of the hill provides an entrance at the second floor.
The sign on the Fitness Center room indicates 24 hour access/use but the in-room guide said something like 7 am to 10 pm. Your fitness hours may vary

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Haven't yet stayed at the HGI on Waterman. Had considered a stay at the Hilton San Bernadino this past winter but we ended up at the Riverside Marriott because of their Concierge Lounge (and no Executive Lounge at the Hilton) - which, of course, the Concierge Lounge was closed (not open) in December because of low business occupancy

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One other option but not as far East is the new ES Ontario - Airport. We were out in Rancho Cucamonga for my daughter's soccer tournament and stayed at the Fairfield Inn nearby (different story). Anyway, that property is brand new - it appears to have opened in mid-June from its
FT thread - but it too is missing a review so far.
David