Wild camping
Wild camping is generally allowed in all Baltic states, but some restrictions apply. In nature parks you should not risk making a campfire, unless there are clear dedicated places, do follow also signs and instructions on info boards. Latvia has close to 500km of sandy beaches, which look very welcoming. However, there are strict rules prohibiting entering the dunes/beach with any motorized vehicle, resulting in high fines. As to putting up a tent or making a campfire on the beach, it is officially prohibited, but many locals still do it. You are, however, allowed to camp near to the beach “where the natural vegetation of the land begins”.
As most of the beaches are surrounded by beautiful pine tree forests, you are very likely to find the ideal place for the night.
You can also often find parking places near to tourist attractions or viewpoints, where you can sleep in your vehicle overnight. Only few places will have restrictions (paid parking places, private land etc) or any objections. Emptying your grey/black water tank may be also possible as some places have wooden dry toilets. Generally, do not expect any infrastructure for camper vans outside camping sites, but you can fairly commonly find picnic tables along the main roads and on/near hiking trails.