Using tools like Briss or
PDF scissors you can cut margins so the page appears a bit larger. Don't cut too much off the bottom because the page numbers cut a bit of that already. (They're both Java, but they do the trick)
You know about double-tap to zoom, right?
My method for pdfs with small text is to rotate the screen (rightmost menu icon) and then fit the text to the screen width. Once you're zoomed in you can pan left or right past the page edge to get the page-turn arrows. (Sorry if you already know this, I just want to be sure.)
I personally wouldn't recommend PDF conversion, unless you're ready to tune/fix the output a bunch. (eg: page numbers appearing in the ePub, incorrect linebreaks)