Need advise-help in Denver Area.

Just read an article that Denver has several stations that offer Bio-Diesel.am curious if any are within easy access of I-70. and what the price is compared to the Flying J and also if any of you have run any of it and if you had any problems.I will be in the middle of a 3k trip towing a 40GN and would hate to have problems in the rockys /ubbthreads/images/graemlins/depressed.gif thanks Stan