Generalize consecutive third tones change rule
The rule about the 3rd tone sandhi is:


When word with the 3rd tone is used alone, or used at the end of the expression, it's pronounced as the original tone, i.e. the 3rd tone. e.g. 雪, 滑雪.
When two words with the 3rd tone are used together, the 1st one is pronounced as the 2nd tone. e.g. 老虎, 海岛.
When word with the 3rd tone is used before other words with the 1st/2nd/4th tone, it's pronounced as the 半三声 (only the first half of the 3rd tone, without the rising tone part). e.g. 卡车, 草莓.
When three words with the 3rd tone are used together;


If the first two words are closely linked, i.e. 2+1 construction, then the first two words are pronounced as the 2nd tone. e.g. 草稿纸, 古典美.
If the last two words are closely linked, i.e. 1+2 construction, then the 1st word is pronounced as 半三声, the 2nd word is pronounced as the 2nd tone. e.g. 米老鼠, 老领导.



井井有条 matches the rule 4.1 and 3, so it should be pronounced as 2-2-(半三声)-2.


  Is the rule that if we have N third consecutive tones, then the first N-1 change to second tones?


It depends on how you seperate the words, to determine which rule should be applied.

Reference:
第三声变调教学教学
第三声（上声）的变调
现代汉语中三个三声连在一起,该怎么变调?