Thank you for your post and you have the good points!
1. What JLPT level would you roughly put me in after completing Nihongo Dojo?
If you you’ve finished Newbie series Season 2&3, Beginner Season 4,5&6, your level would be around N4. After Lower Intermediate series, the level would be around N4-3. You can try your Japanese on the website. http://www.jlpt.jp/e/samples/forlearners.html
2. Which course of action is better?
Firstly, Nihongo Dojo series include Newbie Season 2&3, Beginner Season 4,5(&6). After studying them, here are some options;
move to Upper Beginner series to learn more about keigohttp://www.japanesepod101.com/index.php?cat=66
move to Japanese for Everyday Life series to practice your current Japanese in a daily life contexthttp://www.japanesepod101.com/index.php?cat=83
move to Intermediate series Season 6 to get ready for Lower Intermediate serieshttp://www.japanesepod101.com/japanesep ... urriculum/
3. If I learn Nihongo Dojo series, Intermediate series and Upper Intermediate series, do I cover all the grammar points in the lower level lessons?
Nihongo Dojo series are designed for building grammatical knowledge with structured curriculum. So, unfortunately you cannot learn all the grammar points even if you’ve done the linear study with Nihongo Dojo - Intermediate - Upper Intermediate. As for the seasons other than Nihongo Dojo, such as Newbie series Season 1, 2&3, and Beginner 1,2&3, they don’t focus on building the grammar patterns as much as Nihongo Dojo series do. Since you’ve learned with Nihongo Dojo series, I made one example of the learning schedule here.
Beginner series (currently) >> the options mentioned above >> Lower Intermediate Season 3 - 6 >> (Intermediate series if you like) >> Upper Intermediate series Season 5 to 1 (backwards)
Please feel free to ask any further questions.
Hope this helps,