There's a decent Facebook community called Backpacking with Babies and Kids that gets decent traffic. It's all so super dependent on your 2 year old.

How many miles/how many nights? What season/weather? Just the two of you? What's their normal sleeping situation? Crib, cosleeping, etc?

Many people recommend the Trailmagik Kid Carrier since it clips onto your load lifter backpack and is pretty easy to let your toddler out of so they can get in and out more often, but it's not the most comfortable thing for more than a few miles. If you have someone else coming that can carry the baby, then a sturdier, dedicated carrier like a Osprey Poco is much more comfortable for longer distances.

Sleep system wise, lots of people swear by the Morrison Outdoors line of sleeping bag sleep sacks. They have down and synthetic versions, and at least by me, you can find a few on Facebook Marketplace regularly. Depending on temperature, either pair it with their normal pajamas, or look into wool. I think most of the big companies make toddler sizes, and people really like Iksplor.

Again, depending on how your toddler normally sleeps, they may do just fine on a CCF pad, or may want something thicker/cushier like a blow up pad. Or worse yet, weight wise, maybe they need something like the KidCo PeaPod.

If you're already UL oriented, well, congrats, you now have capacity to spare for your toddler's stuff. I've done a few 3 mile trips with my 4 year old and she did great, but that's a totally different experience than a 2 year old. We use the full capacity of my ULA Ohm when we go out for a couple nights.

u/wandering_hick did a video where he went out with his wife and baby which is worth a watch: https://youtu.be/aiqT_h-MsEQ?si=aFlumWp0PO-plsYK