+1 on the garage door size. Full size pickups are about 8' wide with towing mirrors and some trailers are 8' 6" wide. 10' x 10' or 10' high x 12' wide doors would make for easy access.
Consider putting a garage door on the back side. Sure is nice to take lawn tractors, ATVs, etc. in and out of the shop without moving the vehicles parked inside the main garage doors.
