I was not aware until recently that generator lock-out plates are available for making whole house connections to a portable backup generator. They're really nothing more than a metal plate that fits over the front panel of your breaker panel so that the main line and breaker for your generator cannot be turned on at the same time. And most importantly, they offer a code approved method to directly connect a generator to your home without the cost and labor to install a transfer switch.
Yes. You’ll need DP 30 breaker (for most applications) wired into your panel at the top, lock-out plate, some wire and an RV style receptacle in a weatherproof box mounted wherever you want outside. $150 in parts (depending on how much wire) and probably $300 labor for a basic install.