We did the same thing when we got our first TT. IN fact all you need to camp, you already have. Like us. You learned to pack light, meaning the stuff you bought was compact, and lightweight. So you have an advantage over those who start out with a TT. The things you use that weigh 100lbs, and take up little space. For someone who has never pupped. The same items will weigh 300lbs and take up more room.
So all you really need to start is a Sewer hose, and of course a properly setup WDH. And maybe a brake controller. Don't know if your pup had brakes or not. But you will need them on the TT.
We still use the campstove, And often the cooler stands, and stove stands. Only thing you may no longer need could be the big cooler. The fridge pretty well takes the place of the big cooler. A small cooler for ice for drinks is all we use.
If you are like us. At first you will find using the TT a lot more trouble than using the pup. A lot longer to hook up to the truck, and a lot longer to set up at the campground, and of course more stuff to do to break camp. But after a while you will streamline it, and it will get easier.
When we had the pup. I could have it leveled, setup, and under the awning in 20 minutes. With the TT it is a lot longer.
And towing will be different as well. Not harder but different. You can't see over the trailer anymore. and you will need pay closer attention when passing , and swing out farther when turning. Take it easy, and you will be fine.