Bosses aren’t hard enough to warrant skipping them. These people recommending you skip bosses to avoid fighting them are grossly overstating the difficulty of fighting them.

Lvl 1 bronze/lvl 2 troll + a finewood bow and like 200 fire arrows will dispatch of the elder easily. Hide behind the pillars when he shoots at you and run to the next one when he summons the roots. As long as you have enough hp to survive a hit or 2 you’ll win easily as you’ll barely get hit by him at all.

Lvl 3 mace + iron sledge + lvl 3 iron shield + lvl 2 iron armor + some hp and poison potions will lead to an easy kill of bonemass. Just use the best food you have and you’ll beat him without a sweat. Parry his swipe attack, use the iron sledge on the mobs he summons to one shot them and wait it out when he pukes up poison. He’s even easier now than he used to be as when I beat him easily poison went through armor, and even if you drop below half hp, 1 hp potion should be enough.

Silver armor + iron mace + lvl 3 silver shield + lvl 2 draugr fang with poison and obsidian arrows is all you need to beat moder. Just dodge her attacks, it’s not hard to do. An hp potion might be helpful if you manage to get hit once, but you’ll only get hit if you stop trying to dodge.

Yagluth is probably the hardest, just grab the best food you can plus a frostner and lvl 2-3 blackmetal level gear. You’ll always want fire resist up and you might as well use the bonemass buff too. The key to yagluth is just parrying/dodging the blunt parts of his attack and tanking the fire damage with fire res and maybe some hp potions. You’ll outheal the fire so as long as you don’t let yourself get too low from other attacks without healing you’ll be fine.