Hi Nick, I find if you don't have a deadline hanging over you (e.g. public performance, band rehearsal or showing a teacher what you've been up to) it's next to impossible to stick to practice regimes. Having said that if you're in a band you tend to only practice the set - and in my case scales and exercises go totally out the window. So while you have the time and opportunity, go for it.
A few years ago I got my head down to Joe Wright's pick blocking stuff, Secrets of the Wright Hand I think. Very dry repetitive drills, but they worked (if pick blocking is the route you want to go down). I got a great deal of mileage out of the palm blocking tunes in Winnie's book too (p50-51). I'm sure I couldn't do them now without a lot of practice but they're good fun and a real workout. Those are two things I remember really moved me on a stage.
If you really want to get organised and make the most out of your practice time I highly recommend the book The Musician's Way: A Guide to Practice, Performance, and Wellness by Gerald Klickstein. It's aimed at classical musicians but almost everything in it applies. Every aspect of practice is broken down in a very logical, methodical way. No magic, just a way of planning your practice time in detail so you get the most out of it. The sections on performance anxiety are brilliant as well. The whole idea is that you get into the performance mindset each and every time you sit down to practice. Which makes perfect sense. How many times have you put in the hours on an instrumental only to see it all float out the window as soon as someone is watching? You may as well have not bothered, right? The frets look all different, the cement glove is on, the right foot has a mind of it's own, there seems to be a distracting voice in your ear putting you down. You need to practice the performance not just the technique.
There are simple things you can do to compose yourself: breathing, clearing your mind, focussing, executing, thinking ahead. This isn't hippy stuff, you see all sportsmen go through a little preparatory routine before launching a javelin or whatever. It's more subtle with musicians but it can make a massive difference. You also need to commit the thing to memory in such a way that it will be at your fingertips when you need it. There's good stuff about that in the book and I've worked out my own method for memorising too which I'll be glad to share if you're interested.
I would love to have the time to dedicate to scales and blocking practice. If I was going to get back into scales now I would go back and forth in patterns of three notes, such as 1,2,3, 2,3,4, 3,4,5, 4,5,6 etc or in fours as in 1,2,3,4, 2,3,4,5, 3,4,5,6 etc. Not only does that make for more engaging practice it's a little more musical sounding than straight linear scales and better blocking practice. My wife practices "etudes" on classical guitar which are just scales really but they composed in a musical fashion, so it sounds rather pretty and satisfying when she goes through them. I wish somebody would come up with a similar book of studies for PSG.
This is so obvious (but how many of us actually practice it?): simply trying to pick out the melody of a tune along to a backing track. It can be a real wake up call when you find out you've spent years practicing chords and scales and yet you can't pick out the tune to Are You Lonesome Tonight! I find it so humbling that I don't want to do it even though I know how good it is for improvisation and ear training. If you know the chord positions for a song you can get most of the notes but it's not an easy thing to do from scratch (without some interesting jazzing around)
Anyway those are my thoughts, as you know I'm no expert. The important thing is to get out of the rut of just glossing over our typical go-to songs and doodles and start practicing effectively. Record your current repertoire of favourites. That in itself may lead you to months of discovery and improvement. Seize on every mistake as an opportunity: take it apart and in your own good time, master it.
All the best
Jonathan