This was someone I talked to quite a bit and he had great bits of wisdom. When we would talk about it, he would often say that guitar is like a language and you should learn it like a language. There are some fairly standard blues licks (this site an a good few lesson for them). This is the 'language' of the blues.
You mentioned that you are 'crap at working my way around the fingerboard in blues-esque jams and always stick to 'position 1' of the pentatonic scale.'
Learn the licks. Listen to Lynyrd Skynyrd on most any song but Freebird is a lesson on blues licks. Southern Rock uses lots of these little licks and tricks. AC/DC and Angus Young, the same thing. Lots of tasty little licks that a strung together.
So many players don't spend time learning other players music and I think this is a big mistake. It is a big mistake I made for a long time. It really affected my ability to play. I was lazy in some ways when I practiced. As time went on and I got much more serious, I crippled myself by not taking advantage of the stuff others did before me.
When you learn the licks and apply them to the songs of others, you start to see trends and patterns used by other players and this helps you have those 'a-ha' moments in playing.
My two pennies...and definitely follow the links Chris gave. :)