The raw data delivery was much larger than needed.
LAS file:
  Compressed:
6558720 Bare_earth_tifs
17620992        Bare-Earth_Digital_Terrain_Model
26781696        First_Return_tifs
70847488        First-Return_Digital_Surface_Model
ASCii Ground Points were zip by 7.5' quad, going from 69026816 to 20040704
(Also laz files were grouped by 7.5' quadrangle, eliminating directories of
1693 files.)

img files (do users like ENVI img files?) are not compressed.
Also, many are shipped with rrd pyramid files.  These are obsolete,
as ESRI now supports compressed ovh files instead.
Converting to compressed tiffs

The intensity files have 256 as the no-data values, and so were promoted to
16-bit files.
This proved unreasonably difficult to undo, but compressed tifs reduced
file sizes from 11127808 + 1183744
On the mosaicked intensity.tif, nodata is 0, but there are many valid 0 cells,
so regiongroup.  The full DEM is to big, so 
a) xmin=710529 xmax=733335 ymin=1603210 ymax=1614610  dx= 22806 dy= 11400
##b) xmin=760080 ymin= 1573839 xmax= 799263 ymax=1662961 dx=39183 dy=89122
(notdx=88734)
bse) xmin=791780 ymin=1573839 ymax= 1604532 dx= 7483 dy= 30693 # RCQ
Try raster calculator with bounds reset. and regiongroup; con:maskse if 312
bsw) XMIN= 760294 xmax= 791780 ymax=1600000 vals are 1, 3272270 , 16839456 #
RCQ
...
bsw) xmin 760250 xmax= 785255 ymax= 1621246 ##### group crashed
 try small RQ ssw ymax =1576100
bf) xmin 761690 xmax= 762990 ymin 1621246 ymax 1621390 # RGq
bww) xmin759972 xmax= 760513 ymin 1621246 ymax 1633500 # RGr_tootall

We could also regiongroup border strips if this is too slow or impossible