What to Do in Chiang Rai
Chiang Rai is a small and pleasant little city with some to do, but--honestly--not a whole lot. While it was nice to visit, I would only recommend going there if you're going to continue into Laos as it is the main exit/entry point between the two countries.
However, if you do plan to visit there, here's some things you should check out.
1. The night market
Just like every city in SE Asia, there is a very busy and flourishing market. But, there is some credit to give to the Chiang Mai market - its huge! Imagine rows and rows of vendors. We couldn't even get through the whole thing. In the center of the market, there's live music and a beer garden if you're a bit over the shopping and just want to chill out.
2. Choui Fong Tea Plantation
About an hour motorbike ride away from the city is the choi fung tea plantation. The views are absolutely stunning and it's a beautiful place to enjoy the home grown tea and the beautiful scenery. If you're not keen on riding a motorbike there, talk to your guest house or hostel you're staying at and I'm pretty sure they can set you up with a bus or a tour that goes there. While you're there, you can see the workers picking tea leaves. If you do take a photo of them, PLEASE give them a tip as they do not get the most decent of wages.
3. The infamous white temple
This is the most un real temple I have ever seen and it is definitely worth a visit. The architecture is absolutely stunning and the murals on the inside are absolutely beautiful (and, honestly quite trippy). The temple mixes Buddhism and surrealism art so if you want to see something less traditional, I'd definitely give it a visit.
These are the main things we did in Chiang Rai. I'd recommended staying there 2-3 days. While it has some lovely aspects, there isn't a bunch to do there and I would recommend moving on with your travels if you are a time constraint.
Safe travels!