electric door install. Fender on or off ?

[blazer2007]

I have a 78 short box and I,m finally going to install some electric doors I,ve been packing around for some time. I found some info on where to drill the holes ,but it said take door off ,drill holes and intall new door. Got door off but doesn,t look like much room to drill, maybe with some sorta angle attachment.
What have you done to drill the holes. I don,t really want to take fenders off. I,m running out of room in my small garage. I have hood off, engine out, parts all over and can barely get around the garage now and there is lots of snow outside.