By the way, you only have 11 days in Laos, which is a bit tight to see many places since transport in Laos is slow and long. If you have limited time like you do, plan carefully to avoid spending those days on buses.
You’ll find recent travel times on my post here:
https://voyageforum.com/forum/retour-4-semaines-nord-laos-novembre-2023-d10697270/Luang Prabang deserves a few days with its surroundings (waterfalls, countryside).
To go further north, you can take a bus to Nong Khiaw and then Muang Ngoi, like Grange did. These are really beautiful spots, but it takes time to get there and back.
You can take an easy walk through rice fields to visit villages.
Alternatively, you could go from Luang Prabang to Vang Vieng, which is also very pretty. Stay by the river, explore the valley by motorbike or bike—there are lakes and caves. The town has calmed down a lot since the parties were banned, but the landscapes are still stunning.
Vientiane is also worth at least a day—there are beautiful pagodas.