this might not help , but then again it might . when heading south on i-25 i always see a long stretch of box cars all painted up , there is also one parked on 70 east (i dont know whats the deal with these trains , off the get buffed im sure ) . in denver (santa fe & i-25 ish ) the old rubber factory has a bunch of graff on it . also there are a few murals in my neighborhood (5-points ) id be willing to help out with security if you need it . like i said it might help . ill try to think of a few more places for you .
teh problem your gonna have is most graff on the street sucks , in order to get to the good stuff you really have to look and most places where your gonna find the good stuff is not car friendly. Your best bet is to look anywhere trains and highways intersect , bridges over rivers ect. the big one to remember is most places you will find graff requires a little trespassing , So be careful . Feel free to pm me for further graff info .