Hi! We just got back from camping trip #2 with our little one (now almost 8mo)
our first trip he was 4 months and it was cold- we car camped and lugged a pack and play. He slept in layers (onesie, fleece footed pjs, and a warm sleep sack) and we put a thermarest kids sleep pad under the mattress. He slept like he was at home! (Note- we have the 6 man dome tent so this all fit with a kingdom air mattress for mom and dad)
he had more trouble this trip because it was warm. We were in Shenandoah National Park and even at the top of loft mountain it was muggy and didn’t cool off much. He slept in his pack and play in just footed pjs and was fine.
In terms of during the day our best investment was a kid co GoPod. It folds up like the popular camp chairs but is a stand up (with a footpad so no dirty feet) play space kind of like a not bouncy jumparoo. Don’t forget a hat- more for bugs than the sun. We did a short easy hike with a soft carrier and I had a ring sling for around camp. I also recommend a freestanding playpen Gate and a blanket if your going somewhere big enough once little one is trying to crawl- but at 3mo we didn’t need anything like that.
My best advice is to just do it! It seems a lot scarier before you leave and we’ve enjoyed it both times. Plus we know we’re going to want to camp when he’s bigger so we’re just teaching him early. Good luck!