how can I access the area under cowl / vent

It seems that my new Dart (1970) was parked near a pine tree grove. I found a large pile of pine needles inside the cowl area. I want them out before I get the car painted!

I can see the drain hole on each side by opening the hood. 1/2 hole totally blocked by needles.

It looks to me like the best reasonable access would be to drill a 1 1/2 inch hole on the firewall and then plug it with some sort of rubber body plug, like the ones used on the floorboards.

I was hoping someone here has figured out where to drill...

thanks!

Mark

1970 Dart Swinger 318 Auto