We have extensive experience from Alaska to California, the majority of which was with two 65lbs+ German Shepherds. I wouldn't leave home without the dogs. We are in a similar sized truck (GMC Canyon) with an RTT, and have been adventuring with our dogs in our RTT since our first tent which we got about 10 years ago.
1) We have a "Dog Box" I built into the backseat. I have not yet added the dividers, but the idea is I took 2/3ds of my rear bench seat out and covered that space into a space for the dogs. This keeps them away from the 1/3 that remains where our little person sits. This means long road trips with plenty of room for both pups in a climate controlled, comfortable environment. I recommend not putting them in the box of the truck -- what feels like a small bump for you might be a huge one for your dogs, especially if they are behind the rear wheel, and that increases risk of injury. Even a soft-tissue injury can cause lots of problems for your pup down the road a piece.
2) When we are hanging out around camp, we have tie-outs for the dogs that we can affix to a nearby tree, but usually they get clipped to a recovery point on our vehicle. We transfer the blankets from the dog box to the ground so they have a spot that is consistently "theirs".
3) At night, they join us in the RTT. There are a few ways we use to get them up there. The easiest way to get them up there is on the hood, onto the roof, and in through the side. To facilitate this I stuck grip tape to the hood of my Jeep. If you want something less permanent, a grippy blanket works, but we found permanently sticking the grip tape was a lot easier. We're working on that over the winter on our Canyon to replicate the ease of getting into the tent that way. For the last few trips, we have resorted to lifting the dogs up but that's pretty easy -- an abundance of treats in my wife's hands who is in the tent, and one at a time I just pick up the dogs. When I get close to the tent door, they tend to hop up with front legs and then I just push the bag legs to help them get in. It's really quite simple. Exiting the RTT is the exact same, just in reverse. Again, a couple of handfuls of treats and some intentional time spent getting in and out, and most dogs will be able to work with you to do this safely. The hood-roof-tent method is way easier though.
GIF of Dog Exiting:
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