A lot of people like the Red Rocket and use it as their main base in the game. I tend to as well since none of the other settlements work as well for me as the Red Rocket does. I have my method of setting up shop and moving in but I wonder what every one else does to make it a functional base? You never know, you might find some one elses idea are better than what your doing now.
I don't normally have settlers at the Red Rocket so its just me, Dogmeat, and Codsworth in residence. Companions tend to get sent back to where I found them or I set up a separate town for just them to hang out at. Coventry or Hangman's Alley works well for this.
My favorite set up is to have all my armor and weapons workbenches in the garage area. I also keep one Power Armor rack in the garage are for my personal set of Power Armor. The long open area in the front I use for my kitchen and chemical lab. The hallway behind the counter gets turned into storage for my gear and ammo with a few cabinets, lockers, and ammo cans. The office area becomes my bedroom/office. I keep the desk and computer that is already there and and a file cabinet on one side of the desk and a safe on the other. I like that type of computer way better than the ones with the round screens that warp the words at the edges.
Out side I scrap everything but the vending machines and the ice box. I move the ice box over by the Milk vending machine to open up the back area for me to keep extra Power Armor suits. I do tend to leave the fuel pumps in place but everything else goes.
For power I use two or three windmills on the roof. I have a mod that ups the power output of the windmills up to 20 each so that is plenty.
Defenses I have tried a few variations. Turrets on top of the canopy. Several watch towers made out of concrete foundation blocks stacked up around the perimeter with turrets on top. And my favorite, the full blown concrete wall all the way around with one gate way. I even have two variations of the concrete wall. One with elaborate watch towers on the corners that you can climb up to. The other is just another layer of concrete foundation blocks with turrets on top and no access ladders going up to them.
If I use the wall option I like to place the open steel shack piece along the walls with a Power Armor rack inside and turn them into a mini hanger for my Power Armor collection. The way I build my walls makes the middle row of concrete blocks about three feet in the air. This row of blocks is where I place the steel shack sections. I then place a row of concrete foundation sections in front of the shacks to make a walk way. My Power Armor hangers take up the wall from my gate way, the area where the price sign was, all the way back to the north east corner. I use the whole back wall as well from the north east corner over to the Molerat cave corner. Then you got that little jog in the perimeter around the Molerat cave. Once around that I add more Power Armor hangers along the west wall until I get to where I had to jog around the bushes and billboard signs.
The South and South East sections of the wall I tend to leave alone. The South East perimeter is angled and since we can't angles walls at this point I tend to have a jog in the wall where the South and East sides meet. I wish they had given us some 45 degree angle pieces to fix this.
The area under the canopy tends to get turned into my party/hang out area with pick nick tables or garden furniture and other items. This is also where I place doghouse for Dogmeat to hang out in. I have also been know to run a set of stairs up the back of the building and use the roof as a party spot as well.
In the past I have also built a big building on top of the Red Rocket building. I built in a bar with a dance floor on the first level. Second level was my barracks for my companions, and the roof was full of windmills. But since I have decided to keep the place just to myself I don't see the need to build up at this point.