I second and third the 5-shot 3" target J frame as the perfect gun for those times when you don't expect to need a gun but still feel the need to have one with you. I have a 60-4 in .38 and a 60-10 in .357. I previously had the 60-15 mentioned above (same as 60-10 but with the internal lock).
I started carrying the 60-10 even when rifle hunting after an occasion I found myself on my hands and knees in a laurel thicket helping a buddy track blood from a wounded bear. I quickly realized that the lever action rifle on my shoulder was almost useless in all that brush. Thankfully the bear was 'tits up' when we finally found it. :-)
My other go-to gun that is completely out of the way when on ATVs or hiking is a custom 2" .45ACP on a 1917 frame converted to a K grip frame. I even use the lanyard ring so I can't loose it. It has open sights but I installed a tritium vial in the front.
