+ 1 to everything KY said -- except for the scale.
You have specific issues about crumb and crust, besides the more general question in your thread's title.
Your crumb is too dense because you don't knead enough or knead too much; and/or don't allow enough rise; and/or degas too vigorously on punchdowns; and/or degas to vigorously during loaf formation.
Your crust is too thick because you bake at too low a temperature; and/or bake too long; and/or lose too much heat from trying to humidify your bread; and/or don't employ enough humidity; and/or never got enough "surface tension" on the unbaked loaf; and/or screwed up the oven spring by allowing the bread to proof too long or not long enough before baking.
Mix your dough fairly thoroughly, without overmixing. That is, mix until the dough mass barely cleans the bowl -- if there's a little flour left over, that's fine. Don't overhydrate.
Let it rest for about twenty minutes before kneading. The rest period allows the dough to "autolyse," which makes kneading go more easily.
Knead almost every type of bread dough to the "window pane" stage then a minute or two of extra kneading, before pulling down and letting your dough do its first proof.
Allow your bread to double in volume before "punching down." Don't take your recipe too seriously when it comes to rise time. Think of it as a guide to how long you should wait before you look, but not as a substitute for looking.
When you do punch down, don't actually "punch down." Use the "french fold" technique. That is, gently stretch the dough into an approximatel 15" square, fold it in thirds one way (letter fold), then turn 90* and fold in thirds again. Handle the dough gently, so as to keep as much air as possible in the dough.
After the second rise (again, let the dough mass double in volume), remove the dough from the proofing bowl, and cut it loaf portions.
For each portion, use the "pull down" technique before doing any loaf formation in order to get as much "surface tension" as possible. This is true for bread pan loaves as well as free-forms. While you pull-down, degas as little as possible.
During loaf formation, try and keep as much tension on the loaf skin as possible. Try to lose as little air as possible.
Make sure your oven is well preheated. However long you think is long enough to preheat, add another ten minutes to that.
If you humidify, add a water pan to the oven as well as a spritzer. If you use a water pan, make sure you allow it enough time in the oven so the oven can come to temp. If you spritz, sprtiz in such a way that the door is open as little as possible and for as short a time as possible. Holding heat is more important than thorough humidification.
If you have anything you can use as a heat ballast -- a pizza stone for instance -- use it in your oven, even if you're not going to put your loaf directly on it.
Hope this helps,
PS. IIRC, I wrote most of this to you already but can't recall if it was before or after the few months I was away from CT. Did you try my suggestions? What worked? What didn't?