One thing I would definitely recommend is the mod 'Timing is everything'. I find that it really helps with immersion. You set a level/minimum requirement for certain content. For example, I have Dragonborn to begin after completion of the main quest, and Vampire attacks to begin at level 40,with Dawn guard recruitment starting at level 42. Makes everything seem a lot more organic imo, and is the main reason I have still not played a lot of the content!
I also have one that spaces out the companions quest line, changing requirements, and making you do more random jobs before advancement.
Yeah it still amazes me how much there is to this game. I'm 75 hours into my current play through, and I've only done the Thieve's Guild main quest, started the Companions and done several side and Daedric quests. I haven't even been up to see the Greybeards yet! I see a 300 hour+ playthrough lol.