Agree manually controlling breaker and plugging into a dryer outlet is not good. The issue is forgetting to throw the main before connecting up and powering the generator and back feeding the power lines. A double pole, double throw transfer switch,which completely isolates the power company side, installed by an electrician is best but there are other methods that will work.
A generator breaker interlock switch which, when installed correctly, prevents the backfed breaker and the power mains disconnect from being turned on at the same time. The one I just bought for my breaker panel is made by the manufacturer of the panel and has a code listing.
Here’s what I did:
I had previously purchased a Ryobi 3400w generator for use at a ranch property that doesn’t have power and have used it boondocking with my travel trailer. Is was fairly cheap, had good rating, has an inverter output which makes it better for electronic devices.
I have a Square D 150A Homeline breaker panel that uses QO breakers. I bought the Square D interlock kit that fits my panel and a dual pole QO breaker to go in the upper right position in my panel. The interlock is just a plate that slides up and down blocking the lever of either the main or feed breaker from being switched on while the other is on.
I bought this 50A Generator power inlet box to connect the generator power cable into my panel. This is the same inlet connector as my RV so I could use my existing RV cable setup but will buy a new one separate from the trailer. The cable used will depend on the generator outlet and whether you have a 120/240 or 120V generator.