To chime in a little late:
I think there are YMCA facilities on both sides of the park. You've gotten info on the one near Estes, near the east side of the park. There is (or at least used to be) one on West side, north of Grand Lake I believe. The times I have stayed at the one near Estes (in one of the group lodges), I was warned by other members of my group to avoid the guest dining rooms, that they were terrible.

If your visit overlaps when the leaves are turning, expect heavy traffic at times. In the park, that often means slow (think of large travel trailers that can barely get up the hills and make the curves and refuse to pull over to allow others to pass. It can happen anytime, but there seem to be more of them that time of year).

A little south of RMNP, closer toward Black Hawk and Central City, is Golden Gate Canyon State Park, which has a number of decent trails and views (significant portions of the park are above 9.000 ft.) and is likely to be less crowded than RMNP on weekends. (BH and CC are casino towns, so lots of rooms and often deals mid week. IIRC, at least most of the casino floors are non-smoking.)

TRRed