And will never allow me to blarney My way to getting The fame and the girl and the money All at one sitting.
This quatrain is devoted to what, specifically, that inner sense of obligation and duty (the inner-toad) prevents the speaker from achieving.
The inner-toad makes the speaker unable to "blarney" (persuade, sweet talk, charm) his way to the things he wants. What he wants are the big three: fame, love, and money.
Maybe this internal toad-like quality has something to do with a sense of honesty—his need to do and say the right thing?
It looks like this is all coming down to a "nice guys finish last"kind of ending: work hard, keep your nose to the grindstone, do the right thing, and your reward will be a life filled with, wait for it… hard work and little else.