I second the peep site, love the Williams peep and front fire site on my Rem 760!
But if you really want a scope, stick with something in the low fixed power range for shots under 50 yards. A 4X scope would work well and give you plenty of magnification for the unexpected 100 yard shot...
for that kind of shooting you can get away a lot cheaper. i have a $50 bushnell sportsman 4x32 on my marlin 336d 35 and its ideal. the site picture is bright and the FOV is wide and clear. shoots one holers all day at 50 yards. so accurate, its almost boring. that said, its a bit big. its the one on the bottom of this pic.
on my 336 sdt 30/30 i bought a Nikon Monarch UCC 1.5-4.5x20 and it was $179. the talley extra low mounts were $50. it is perfect and fits the small guns much better.
the burris timberline is a good match for the marlins as well and at some point i will probably switch out the bushnell for one of those just for the size factor. either way you go, i highly recommend the talley one peice mounts.