I've been playing RM since the late 80's and I've not run into the difficulties you seem to be having. The best option to help with your search are the Shadow World Companions (IMO). There are some fantastic adventures in each book. I've taken single adventures from several books now and used them as a one-off for a quickie session with a few friends or I've injected adventures into long running campaigns. I've even based two different gaming groups in Gryphonburg with the Green Gryphon Inn as a home base. I've never used a single Companion to run through the entire campaign as written in a module. There are two that I would love to run however, but I would either have to tweak some details or just run it as a campaign completely isolated from my existing game world. There's no rule that states you have to do any of these things, other then to just have fun doing it. It's a buffet, my friend! Take the bits you like and pass over the ones you don't.
As for the micro details such as "read this part to the adventurers" and "don't read this part to the adventurers" well, those little bits exist in the Shadow World books too, just not in excess and as a GM, you should be able to have a little more freedom than saying to your party only what is written on the piece of paper.
I've played Temple of Elemental Evil and I always thought it would be perfect for RM and Elemental Companion. I don't have the actual module, but I would gladly spend a day or two converting it.
As for the PC levels needed for the adventures in question, they can usually be determined by looking at the level and numbers of baddies the party faces. RM also makes it very easy to add or to remove baddies or to increase or decrease the levels.
Where I differ in preference is in where you enjoy the way modules are written in D&D. I don't like the restrictiveness and lack of freedom of those modules, but that's just preference and play style. D&D modules always felt to boxed in with no room for straying off the path. I play from time to time only because I enjoy hanging out with the friends who play D&D, but the modules are definitely not why I play D&D. Like you, I love the realism of RM and I love the freedom for creativity when I'M GMing and when I'm playing.