There are some great ranches in Texas to hunt Mule Deer. Many of them have greatly improved their high fences, so the deer are more secure. And with the advances in camo designs, some of the Feeders are scarcely noticeable in the pictures/video that you can take. About the only thing left to address is the sound caused by the auto feeder turning on, but the deer are conditioned to come to that sound, so you would not want to change that feature. Many of the serious hunters in Texas will just turn the propane up on the heater, and get the sound of the heater to drown out the feeder sounds.
But, to your question, for the age class of Mule Deer you want to kill, there is no need to wear Camo. There is just not a need to camo up when riding an ATV, and as we have been lucky enough to have Bush elected to the White House, we now see the proliferation of access to all of the Public Lands of the West by ATV riders. This has resulted in the deer being conditioned to the presence of ATV's. And as there is no need to get off an ATV when hunting Mule Deer, it is now fairly common to see all the deer being harvested by the age of 3.5 years, like you are seeking.
The other good way to conceal while Mule Deer hunting is to find an old Herford or Angus cow hide and drape it over you. As the Bush Administration is now rolling back all the restrictions on grazing practices on Public Lands, this method will only become more and more effective as the cattle remain on Public Lands for the $1.35 per month the goverment gets to feed privately owned cattle.