At the cottage, so I have my annual period of dark skies for some backyard astronomy. 
I’m not a bad star-hopper, and have no issue finding, say, Andromeda, Bode’s or the Cigar Galaxy. I’m damned if I can find the Pinwheel Galaxy, though. I’m not clear on why that might be - it’s magnitude is between that of Bode’s and the Cigar, and it’s location looks to be pretty straightforward - roughly an equilateral triangle with the last two stars of the handle of the Big Dipper. Suggestions?
It’s simple - it has very low surface brightness. The magnitude measures total brightness. M101 is larger than M81 or M82, so the light is spread out over a larger area. I’ve only seen M101 under very dark skies (using large binoculars), while I can see M81 and M82 from my front yard.
Ah. Thank you! So would I be better off with a pair of binoculars than my 4" telescope?
M101 should be visible in a 4" telescope M101 if the sky is sufficiently dark, and magnification is low enough. I’d aim for exit pupil of 5~7mm; for 4" aperture, that would be 14x to 20x magnification.
Given the same aperture and magnification, two eyes are better than one. But if you compare binoculars to a larger aperture telescope, it’s hard to say. If it’s a choice between 11x80 binoculars and an 8" Dobsonian, for example, I think the Dob wins easily. 11x80 binos vs. 4" refractor might be close.