Yeah, it's taken a lot of creativity to catch-up after a certain point. And sometimes even skipping small bits just to ensure the lms craving is covered and you get an understanding of the major plot points.
Royal Road links to Japtem.com which was useful up to around volume 16
If you're done with Volume 18
Volume 19 summary is your best bet after you read volume 19 chapter 1
http://www.royalroadl.com/volume-19-chapter-1/
http://www.royalroadl.com/forum/viewtopic.php?f=52&t=2438
Volume 20 is fully translated
http://www.royalroadl.com/volume-20/
Volume 21 summary is decent until chapter 4
http://www.royalroadl.com/volume-21-summary/
After that, there are still a couple of summaries that are still pretty useful for the first bit.
http://www.royalroadl.com/summaries/
The good ones are also sorted by chapters, so you hardly realise it's not a word-by-word translation.
There are also some random translated chapters here & there, so you're relatively ok until around volume 24
Thats when it gets really difficult, the summaries from around 25--31 are basically Question & Answers sessions
The theory being that you read the Google Translated (GT) versions that are available in the royal-road forums, and any questions you have can be answered in that summary page.
Honestly speaking however, those are a huge chore to read, as you can imagine with Google muddling up translations, so thats where a lot of my skimming came in.
Chapter 32 is another decent chapter-by-chapter summary http://www.royalroadl.com/forum/viewtopic.php?f=52&t=2449http://www.royalroadl.com/forum/viewtopic.php?f=52&t=2449
And then there are more shorter summations between ch 33-38 which are at least easier on the eye than the GT.
vol 39 gets back to a chapter-by-chapter which finally brings LMS back to being readable again