There is no way I would want the Bowen Ranch road and its offshoots imporved. Katrina I would propose the exact opposite. The road should be rough and the hike long. I have seen California explode with people. The visitors more numerous at the springs. This trend will continue. I my explorations of Hot Springs throughout the US, the easy access hot springs become trashed, destroyed, then closed.
The effort to get to natural hot springs is a great filtering device. Those most likely to trash the place are usually those who dont want to make any effot to get there. Look around elsewhere in the National Forest. The pullouts, the party spots, the easy campsites-- they are trashed. However, when you get away from roads, or you follow rough roads, you will quickly find that the forest is much cleaner.
If anything the hike to Deep Creek Hot Springs should be longer. If we want to look long term, look into what the growth in California is going to do, the development of the Antelope Valley are more and more are commuting, what would close the hot springs due to exceseve human impacts-- making the trail longer to Deep Creek Hot Springs is a very good option. They definatly dont have the money for a full time copy baby sitter out there.
Katrina: by improving the access to the hot springs you are paving the way for more destruction of Deep Creek and its eventual closure. What that place definatly does not need is easier access to the flotsam of society.
To be honest I am amazed you proposed this. Come on: think!!! Or rather: think with wisdom!