Hopefully EssArrBee can answer this one :)
I've been following the Fear and Loathing New Vegas STEP guide and I believe I've hit an impasse.
It looks as though the use of Realistic Wasteland Lighting Enhancement (RWLE) and NV InteriorsProject A Room With A View in tandem produce a conflict.
On the left is a screenshot of both mods installed and enabled. On the right is a screenshot of RWLE disabled in the left pane of MO.
I've checked for direct conflicts in FNVEdit and there are none, but it looks as though RWLE weather/image space changes something vanilla that supercedes A Room With A View.
It would be nice if a work around could be found, but I suspect that the use of both mods simultaneously will need to be revised.