When Homer needed to find a way to climb the Glass Dome, he goes into a shed and the audience see a Jetpack, but Homer went with the Super Glue. This very well could be Homer being an idiot of course and it looks like it is, but what are the possibilities of Homer actually knowing how to use the Jetpack? In his mind, The Super Glue was the safest option for him because it was more practical for him and sure enough it worked.
Homer's emergency plan to move the whole family to Alaska seems like something that came completely out of the blue and was made up for the movie. However, the episode "Homer Badman" had Homer suggest that they move under the sea once it became clear their reputation in Springfield was tarnished forever. It would appear he (eventually) realized how infeasible that was, and made some revisions.
What were the other four options on what to do with Springfield, other than being sealed in a dome? All Cargill was able to say before Schwarzenegger picked one was that they would each "cause untold misery".
Similarly, what were the other four options to blowing up Springfield? Though they might not have been as bad since Cargill manipulated the president into picking that one.