Thanksgiving is too big a Glamis weekend IMHO.
Not even really a weekend as the crowds start showing up the week prior and stay through thanksgiving.
If you just want to sit at olds and watch the crowds then by all means.
On any big holiday weekend there will be lots of big money rolling around out there to look at, but also way crowded and lots of rangers.
Plus, on any big weekend competition hill will be closed down at night.
I prefer the "off" weekends. Hell, I'd go midweek right after the wind blows hard if I could arrange it more often.
Season start in October and die hards with high heat tolerances ride through May.
As far as spring break goes, if I were you I'd go to San Felipe Mexico.