I myself hunt the same type of thick brushy area with a few openings out to 100 yards and I have my trusty Marlin 336 with me, now...only if I could get a chance to use it!
A word of advice, while I'd recommend a Marlin, you may be better off buying a used rifle, as after Remington bought out Marlin and moved the manufacturing to their factory from Connecticut the QC of new Marlins has been awful! Just Google "Remlins" and you will find horror stories of shattered stocks on brand new rifles after only 1 shot, poor craftsmanship, machine work etc.
I'd recommend looking at Gun Shows, and if you find one, look for the little "JM" stamp on the barrel and that it was made in Connecticut. Either that or you could try to find a Winchester 30-30.