I don't know how accessible the Yuma ranges are by vehicle (though I-8 runs right by them), but we did a lot of low level stuff through the R2301W just east of NYL. Also the El Centro ranges are pretty close. IR289, VR1266/67 are common ones we did if I'm not mistaking numbers. Anywhere around the northeast side of the salton sea is a good place. There is a turn point right at the north of there where most guys will do a pretty aggressive turn at 300' to get heading SW over the lake towards the mountains. Just prior to there and due east of that little airport on the east side is a really good ridge crossing where guys will go inverted right up against the ridge line. As for Yuma, much like the China Lake/panamint/saline valley areas, the whole thing is a low level area iirc down to like 100'. I did my 100' AGL demo out there just east of the first row of mountains in the vicinity of "TACTS airfield" (probably not on a sectional). Hope that helps!