Check the gas supply tube to the pilot and make sure its not crimped, or has a hole worn through it. On my 1969 Bon Voyage, this tube is aluminum, and had been installed in such a way that it rubbed against the access door, eventually wearing a pin hole at a bend point (this took 20 years). The hole was hidden from obvious view and it took a while to figure out the problem, but the hole kept gas from getting to the pilot, preventing it from lighting. Hah, the hole was so small I was able to do a field repair with duct tape until we got home! Another potential problem could be that the thermal bulb has gone bad... keeping the pilot from lighting. Both the aluminum tube and bulb assembly can be found at vintage trailer supply sources. Good luck!