I will share my experience as I was in a similar boat as you last year. I hope it helps a little.
After trying many things, the method that worked for me was to spend about 1.5 months on each module. About half of the time, I was doing the recommended structured practice and after that I was taking a break playing songs that I like. My goal was not to perfect every exercice in each module like grade 1 or 2, it was simply to try it for a few weeks and then move on.
It was not easy to keep the grade 3 structured practice as I found some exercice boring, but in the end, I’m happy I stuck with it. I have to admit that some modules felt like a chore to me and I would have prefer just playing songs. I had to start the grade over 2 times to accomplish it because of lack of motivation, but it was worth it as many things feel much easier now in the intermediate grades.
My schedule for each module looked like this :
Week 1 : Watch the videos
Week 2 : Follow the suggested practice routine for 4 days + 1 day Transcribing
Week 3 : Follow the suggested practice routine for 4 days + 1 day Transcribing
Week 4 : 1 last day of practice + 1 last transcribing. And then start fun time …
Weeks 5-7: Work on songs that you like (not necessarily related to the module).
For me, also, grade 3 was the start of my big project of learning all the songs in the JustinGuitar Rock Songbook. A really cool project that I’d recommend if you are into rock. They were not all my favorite songs, but each one builds on top of the other in terms of skills and it definitely had a big impact on my playing. See my post for more details Math07 JG Rock Songbook Project (10 out of 15) - 3 songs added 3 June 