an old quilt: how much effort to make it usable and do I want to?

I have a lot of family quilts....most in great shape with intricate patterns, tiny stitches and some, because we used them growing up a bit more worn, like the one my aunt made from my dresses that I used and used and even took to college...it's still a usable quilt for a single person.

The one I'm trying to decide what to do about is a thrift store find that I love...such a hodgepodge of pattern and color and all hand stitched in not so tiny stitches....just a heartfelt piece of work.  I think many of the pieces are flour sack prints...

The problem is the cotton batting has become very lumpy, almost pebbly, not soft and even anymore at all.

I can't decide if I would regret unstitching the top from the bottom...removing the lumpy cotton and then adding a thin cotton blanket or flannel sheet between the top and bottom before hand quilting in the same manner as originally done?

I guess I'm hesitating because once begun I've committed to the whole project...and will the quilt lose it's charm by my interference?

I usually try to pick up a hot weather project to do indoors on those summer afternoons when I don't go outside....this is one choice.

I've had it sitting around for several years now already in my undecisiveness.

Thoughts?

It seems to me that just adding a new back with new cotton fill might work.

After attaching the new backing and cotton, the whole piece would need to be "tatted" (may not be the right work) or attached every so often (as the original was).

thanks Anne!
that's about what I was thinking although I want to separate the front and back and remove thhe old cotton fill.
I like a thinner quilt and probably wouldn't want to spend what new cotton batting might cost.  I've used a thin cotton fabric for fill before and it feels nice for a light weight quilt.

I think the reason the cotton fill in this quilt matted and got lumpy was because the rows of quilting to attach the front, fill and back of the quilt were pretty far apart...also I suspect it was machine washed, as I do my old quilts occasionally but the quilting on them is quite close.

oh my. I dont have any helpful suggestions but I feel for you. I have a handsewn quilt that my aunt made out of scraps from the clothes she made for herself. I found it in my mother's basement when she moved and took it back home with me. It is one of those foldover-triangle type things that each triangle is sewn together, so no quilting per se, but some triangles have started to pull apart, some triangles have deteriorated.... obviously after being neglected in the basement for decades it got washed (and I do wash it every few years)....
I decided I would just enjoy its life, and not worry about its appearance. I have oversewn the failing seams with a crisscross on my machine (as if it were an overlock stitch) in matching colors so it's not super apparent, and every few years there's a new line that needs reinforcing. If you look closely you can see this frankenstein stitching, but from arm's length it's just more crazy in a crazy quilt. Totally not "the right way" to repair, but the quilt got a new lease on life.
Big props to you for trying to fix it the right way. Me with my cheapskate tendencies, I'm thinking it might be easier/cheaper to thrift a comforter and after you take the back off, just stitch it on there and quilt directly, but again, I have to do everything the wrong way..... :-)

What about a flannel sheet as backing?  Maybe with that you would not need cotton fill.

Tereza, I'm not sure there is a 'wrong' way...I just want to preserve the feel of this quilt and make it soft and comfortable again...useable (or take it back to the thrift store and let someone else enjoy the challenge).
As it is the lumpiness gets in the way....I have done your method of repair plenty of times!

The backing is solid (although a couple of the pieced parts have bled through) so I want to use both it and the top, only adding new 'fill' which will likely be another thrift store find...a light cotton blanket or a flannel sheet maybe.

 It is one of those foldover-triangle type things that each triangle is sewn together, so no quilting  

Tereza, Is there a simple 'how to' for making this type of quilt?

I have no idea. I'm only guessing looking at the quilt-- squares of fabric and what looks like a rough flannel-type filler were cut and folded over into triangles and hand stitched shut with the edges on the inside, and then hand stitched together with other triangles to make blocks, and other blocks to make lines, and etc etc. (lots of hand stitching, this aunt of mine had a famous garden in the summer but now I know what she did in the off season!)

I wouldn't undo it because it could stretch or tear where the stitching was tight. I would embroider it to match the fabric pattern.