i had an experience just like last year which was my first year hunting bear and first experience with bear that close!You can shoot a sow in the fall with cubs but not in the spring.
If your packing a 12 ga setting up on the ground shouldn't be a problem. I have set up on the ground a few times with the bow and it is a whole different experience than being in a treestand. Twice I've had them close enough to spit on. One experience was a sow and two cubs. I never moved a hair. The second one was a big sow with a huge "V" blaze that I'd been trying to stick. She would come out and circle the bait at about 60 yards every time, all the way around until she caught my scent then she would just fade away. I figured I'd fool her, next time I come in I swung out to where she circled and set up just off the trail tucked back in the fir trees. She come in just like always and started to circle except this time she went out a little further and moved around behind my position. When she caught my scent she didn't bolt but started to walk towards me. I had no shot where I was stuck in those small fir trees as the only opening I had was towards the trail. When she got to about 10 yards she angled a bit to pass on my left. I drew my bow as there was an opening in the trees 3 steps in front of me on the angle she was going. When she got to that opening there was a dip and all I could see was her back over the little firs. I held full draw thinking that I was in a real bad spot. She took a few more steps then let out a big "Whooof" and made like a D8 dozer, thankfully going the other way. It was a minute before I trusted my legs to stand up