Car Trailer Width Question - Help!

My trailer(a 1968 Homebuilt) is 73" inside the rails and my 67 Dart fits on it with room to spare, the biggest problem is that the fenders(didn't have any until 2 years ago) sit pretty highg and I can only open the door about 6 inchs . I hauled a 73 Chevelle on it and it was tight, I had to watch the front wheel and had about an inch to spare on bothe sides. My brother used the same trailer to haul his Modified (GM metric chasis) and we had to 15" wheels with stock tires that he had to put on the front to clear.